# Mapmaking Discussion & Philosophy (WIP/Critique) > Regional/World Mapping >  WIP (sort of tutorial to be) : Climates, applying Geoff's Cookbook at detail (some)

## Pixie

Hi folks.

Been working every now and then at the detailed heightmap of this world but I also spent some time in related projects (some hobby free time... which isn't as much these days as I would like it to be). One of them is this one.

With a fairly detailed map of the one continent, I could work a nice climate map as well. This I did, and then redid, and then again. And every time I added a little more depth and a better understanding of climate. I also used Geoff's Climate Cookbook everytime. In the meanwhile other members were also working on climates and I thought there could be more in terms of guidance for that. Hence, I thought I could, perhaps, redo my climate map in nice smallish steps and make it public.

Should the outcome and the process be of any "learning use", I will turn this into a pretty pdf for tutorial purposes..

So this is how I am doing it:

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## Pixie

As I said before, my canvas is a topographical map I am working on, which is, at this stage, detailed only for one continent. That is the continent I am working on, it's called Palamb (and there is one very large country in it also called Palamb).

The first step is to have a regional/continental map which is clear of all clutter but shows the physical geography. This map needs to have latitude lines, preferably (or at least) the equator, the 30º and the 60º lines. I got my whole world map onto g.projector and then tried a few projections. My choice went to Hammer projection. It shows a relatively large portion of the map, in places emphasis on the center of it and visually it keeps an idea of the planet as a sphere.
So I exported my base-map-to-be from g.projector with this end result:


You will see in the next post it is important to show not only where land ends but also where the continental plateau ends. Those boundaries between shallow waters and the deep ocean are very important for currents, and oceanic currents very important for climate, so go through the trouble of setting them, please. On my map, that is the light blue around the continents.

As you can see, the latitude lines are visible, there is ample space for scribbling on top of it all and it gives the viewer a clear view from equator to poles. Task #1 is done.

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## Pixie

So now you have a base map, you will add a bunch of layers on top of it... a lot. So get yourself onto a "layers" drawing program (in other words, Paint won't do).

Time to find the "logical" ocean currents. Now, this is pretty easy and I'll trace it in a few steps.

1. Close to the equator there are two currents, flowing westwards. These are the strongest and the first to be drawn. In between them two (most of the time, exactly on the equator) is a counter current flowing eastward - Draw these currents in black. As the currents are more or less parallel to a latitude line, there isn't a significant exchange of heat between the water and the surroundings.

2. As these two strong currents meet a continental basin (not necessarily the shore, see last post) they get diverged away from the equator (northern one will move north, southern one will move south). They will stick to the eastern border of that continent approximately until somewhere between 30º and 45º of latitude. During this time, they release heat brought from the equator and are, hence, warm currents - you should draw them in red.

3. At the 45º West -> East winds (the westerlies) are blowing strongly enough to create an eastward current. However, this is no sudden right angle turn, it actually starts much sooner. The warm current you drew is no longer as warm, is now moving in a more or less stable latitude and will not exchange heat - draw in black.

4. As soon as this current meets continental shores, it spreads north and south (and wikipedia says it sticks pretty glued to the coast both because of the properties of the colder water and because the westerlies don't blow offshore at these latitudes on the western coasts). The currents moving back to equator will take reasonably cold water, which removes heat from the air in the region they pass through - draw them blue. The part that flows north takes relatively warm water to the poles - draw in red.

5. All it's missing is the circulation at the poles. It isn't clear in my map because the continent is mainly tropical/equatorial and it wasn't needed. All you need to do, if you have polar oceans/seas, is to close the loops, keeping the color code for currents moving poleward (red), "equator-ward" (blue) and laterally (black). Remember, unless you close every loop, you are saying water piles up somewhere, and if you are saying that, you are wrong  :Wink: .


On the map there are a few currents which have been placed to close the existing loops. Kuy and Santellan currents are the feeding currents for the Northern Equatorial. Since the latter needs to exist the loops needed to exist and to be closed. The Kuy current is also forced to exist as the path eastward is blocked by the warm Palamb current that is moving north and partially blocking the West-East surface movement.

The Hondan Southward current is generated following the same logic as before. Warm water flows south/southwest from the equator in every continental shore facing east in the southern hemisphere. This generates the said current. To close that loop there's the Ohamana cold current.

EDIT - noted a couple of errors in the instructions for the temperate westward currents, I think it's better explained now and error-free.

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## Pixie

From now on, all steps will come in pairs. That is to say, you need to make maps for Winter and for Summer. But best call it July and January - they represent the extremes in terms of how far south or north one can find the hottest areas on a planet and not the typical temperate seasons.

So, new layer. And you can toggle off the currents one. This new one could be called "January weather outline" and will contain the major features in the atmosphere.

The main features are the areas where air rises, causing rain, and where cold air from the upper atmosphere sinks, causing blue skies and moisture free air. In simple terms, here's what matters for the map:

- Close to the equator is the Intertropical convergence zone (ITCZ). Humid air from both tropics meets in the equator and rises, releasing it's water content. Draw this as a very blurry line as it isn't a well defined place. Inland, the ITCZ moves up and down according to the seasons (it is at is northernmost point in july and at its most southern in january). In the oceans it hardly moves because the surface temperature of the oceans varies much less. The ITCZ has a year-round bias towards the hemisphere with large continents, if you have those - this happens on Earth, with Eurasia. On the other hand, if you have large oceans, the ITCZ might split into two, with a clear sky area just over the equator - this happens on Earth in the Pacific.

- Close to 60º we have the Polar Fronts (PF). This is even less defined than the ITCZ and moves southward/northward during the year in the same manner. Here, the cold air from the poles meets temperate air and again, clashing air masses will rise and make rain. You should now have three East-West lines.

- Around the latitude of 30º, on every ocean, a high pressure center will form. This is where the dry air sinks. Those high pressure zones are more or less stable around the year but they also move up and down as the seasons progress. They tend to stick to the eastern side of any given ocean, not far from where the cold currents moving to the equator appeared on the previous map.

- Contrary to the high pressures at the oceans, the warmest areas of a large land area will be indeed very hot and that causes the local atmospheric pressure to drop. This generates low pressure centers, which only form if the land mass is pretty big, at latitudes close to the tropic lines but maybe as far as 45º (equal latitude to the tilt of the planet, I'm assuming 23º as on Earth).

- In this particular map we can't spot these ones. But, usually, terrific high pressure centers are found at the center of the continents when at their coldest - which means, during Winter. On Earth this happens only in the core of Eurasia, north of the Tibetan plateau.

 ... January

New layer for July...
I struggled a bit to envision the movement of the ITCZ in this continent because of the huge mountain range on the eastern side. There were two options: either it shifts between north of that range and south of that range during the year or it is an area where it is stable throughout the year. Given the proximity of the ocean, I went for the second.

 ... July

Note how the PF's have moved up a little, like the ITCZ in same parts. Also, the high pressure centers moved to the north, only slightly, except for the Western Danip High Pressure Center, which was able to stretch eastwards with the change of position.

Have a look at how atmospheric pressure and wind formation happens on Earth with this awesome link, for comparison:
Global Climate Animations Circulation and Winds

... and once you're happy with your work...
Task #3 is done.

(EDIT: corrected January map and added extra instructions - to add low pressure centers in continents, when warmest and high pressure centers, when coldest)
(EDIT 2: added link to Global Climate Animations)
(EDIT 3: added further instructions for placing the ITCZ)
(EDIT 4: made clearer instructions for continental High Pressure Centers during Winter time)

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## Pixie

Now it's time to work out the dominant winds. This stems directly from the previous work, the distribution of atmospheric pressure, and it's simply adding on top of it.

So get a new layer to scribble and a rather thin and simple brush. This time all you do is drawing arrows.

Keeping the previous work in sight (but you can reduce its opacity, to clear the view if you need, like I did in the example below), your job is to "preview" which way air moves near the surface. The key point is that air whirls instead of moving in straight lines, like the whirlpool in the tub. And it circles in opposite directions in the northern and in the southern hemisphere, as well as in low pressure and high pressure areas.

Here's a kind-of-step-by-step approach:

1. northern hemisphere: air surrounds the high pressure circles clock-wise. It will drift into the PF moving eastward and into the ITCZ westward.
2. southern hemisphere: high pressure circles get surrounded counterclockwise, resulting in drifting into the PF and ITCZ in the same direction as before.
3. even if pretty far from any high pressure center, air gets sucked into ITCZ or the PF just like you worked out before.
4. low pressure centers in each hemisphere suck air, it whirls into them in the opposite direction to the high pressure centers in that hemisphere.
5. winds north of the polar fronts: they always draw a kind of curve from the pole to the west, into the PF.

If you get confused whether it's clockwise/counter-clockwise (as I did so many times), use this for reference:


Now, don't shy from drawing arrows but don't draw arrows very far away from any of these influences. There are effectively areas in a planet where the winds just never blow strongly...

Again, this can be of assistance if you want to compare your prediction with a planet that we actually know well  :Wink:  
Atmospheric Circulation and Winds

Here's my result:
 ... July

And since this example has absolutely no land out of the PF, I didn't bother drawing wind arrows close to the poles on this one
 ... January

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## Schwarzkreuz

Nice work. I dont always try it this road for realistic weather conditions. Its somehwat a huge topic of its own, so nice to see someone tries that way.

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## Pixie

Thanks scharzkreuz. Yep, it's a complex topic (next post - rains - is a huge one). But some people like to indulge in it, and some, like me, might get obsessive over detail  :Smile: . Hardly necessary for the typical map one can find in the guild.

I shall add a disclaimer, maybe, advising that it will take labor-days to get the climates done.

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## Pixie

So, here comes the rain.

This is the trickiest and longest task and it takes some time. Geoff's Cookbook has 8 different factors to include and we will cover them all in a layer upon layer technique to add them together. As before, this needs to be done twice, for the extreme months of January and July, and the previous layers of sea currents, atmospheric circulation and dominant winds will all be used. 

Also, you need to have a good idea of elevation. Not necessarily an over-detailed map like the one I'm using in this example, but something with a little more detail than just the linear super-ranges. If you haven't got anything else than this, you can make a draft layer marking other ranges and elevated areas (plateaus, like southern Africa, East Africa, Iran and Turkey, Central Brazil, have climates specific to their elevation, so you can't ignore that sort of terrain completely)


Now, first thing to do is to create a few layers to work on, you can call them
- baseline rain
- ITCZ, extreme
- ITCZ, moderate
- onshore winds
- mountain rains
- warm coastal currents
- polar front

I am going to break down what to do for each layer, then we turn all this into a single layer mapping rain in colors ranging from dry to very wet, which we will relate later to Koppen's climates.

1. baseline rain
All the layers will be colored with one color only. I use a not-too-bright blue, RGB:100.100.150. Brighter colors will make the end result hard to read.
For the baseline rain you just select one very big area (the whole map if you want) and bucket-fill it with this color. Then toggle off the layer and toggle on atmospheric features. Make a selection (using the lasso tool) around the high pressure centers (stretch it further east and west than the actual centers drawn before). Don't loose the selection, toggle off that layer and toggle on the dominant winds. Adding to the selection choose coasts where the wind direction is offshore and the areas behind mountains that winds cross (normally called the rain shadows of those mountains). Still, keep the selection. Toggle off the winds. Go back to the baseline rain layer and just press delete. Now your initial baseline rain has gaps big and small. Toggle it off again so you can clearly see the land. Make a selection encompassing all land that is far away from the coast or protected from coastal influence by mountains. Back to the baseline rain layer and delete that as well. The end result, for me, was this:

Toggle it off, and leave it there... 

2. ITCZ, extreme
Same process, but this time way faster. Toggle on your atmospheric features layer. Make a selection that covers the ITCZ you marked before. Bucket fill this with the same color as before, in the appropriate layer. It's done. Here's what it "could" look like:

In hindsight, I may have made it a little too narrow. Because it's a simple single color area, it's easy to adjust and you can always go back at any point. 

3. ITCZ, moderate
The ITCZ isn't a very defined area and its effects may be both broader and stronger than any other effect, so we have a second layer for it - no other factor weighs as much.
We're already in the third layer. Make a much wider selection than before (I'd say, at least twice as wide) and bucket fill in this new layer.


4. Onshore winds
Obviously, you need to view your dominant winds layer for this, but also the elevation map. With those layers visible search for every piece of coast where the dominant wind blows inland from the sea. Select the area where these winds would carry clouds/moisture into. If it's a wide plain, the whole thing, if it's a mountainous coast, only up to the mountains, if they blow exactly onshore, further inland, if they are parallel to the coast, only a thin strip of land. Islands, it's plain to see, get onshore winds whichever direction they blow, so cover them in your selection as well.
My example works out this way:


5. Mountain rains
For this one, you need to see the dominant winds and the elevation map as well. Wherever winds meet mountains, select the areas just before the mountains. The extent of those areas will depend on the kind of mountains, but the amount of rain would also depend on the kind of slopes, so don't worry about this too much (we need to keep it practical to a certain level). If a dominant wind is coming from a particularly dry area (a hot inland region), ignore it in this step as it wouldn't create rain even against an everest style concrete wall).
Plateaus also work as barriers for this, although you need to extend the selection somewhat into them and not just "before".

If the layers are looking a little strange to you, don't worry. In the end they'll get added in a neat way into a rain patterns map.

6. Warm coastal currents
These influence the weather in a large area. Unlike cold currents which are narrow and stick in the coast, warm currents are more spread out and the moisture they carry gets transported by the dominant winds. So toggle on the sea currents and the dominant winds layers. Your selection will encompass the red arrows you drawn for currents but stretch it into the areas where warm currents meet cold currents and also in the direction the winds are blowing in the area. A warm current with onshore winds and a deep coastal plateau will generate a very large area of influence.
In the end, without loosing the selection, toggle off the current and winds layers and have a look at the elevation map. You may have to cut down the selection a bit if you went inland over mountains - those areas should not be influenced by the oceanic affairs.
This layer ended up like this for me:


7. Polar Front (lastly, but not least)
The Polar front has a broad effect as the low pressure centers that form in it are prone to move about and form in different locations. So all you need to do is to select a wide area around your previously drawn polar front (as seen in the atmospheric features layer). Now, these low pressure centers make an eastward movement between birth and death so they normally carry more moisture when they enter the west side of a continent than on the eastern coast. Because of this, make your selection wider in the West coast, stretch it inland but narrower over the distance and, eventually, non-existent on the east coast (this depends on continent width and on mountainous terrain in the way).

Because this continent is mainly tropical/sub-tropical, the PF has virtually no influence on its weather... less to worry about.

And so the different factors have been considered. Apart from the ITCZ, which we accounted twice, the assumption is that they all have the same weight, which is naturally wrong, but it's a compromise we can work with. I'll continue in the next post to break give you a break.

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## Pixie

The ultimate goal will be this (here shown covering only a small area)


In this image I labeled the 5 levels of rain we need later, in order to compute the climates: DRY, LOW, MODERATE, WET and VERY WET (this technique will eventually yield a 6th level - even higher - we can call it INSANELY WET, but treat it as just very wet  :Smile:  )

Here's how we transform the previous stack of layers into this:
- set all those layers to "screen" mode (instead of normal) (can please any photoshop/gimp savvy person explain what this means, if necessary?)
- duplicate them (as not to lose your work in the next step and easily go back and quickly correct anything if need be)
- make only the duplicates visible and turn off all other layers in the file (all, including background)
- when you set them to screen mode, they turned very whitish, but now there are areas in the original color and brighter areas where those layers superimpose, right? (just checking)
- merge visible layers

You can name the resulting layer with an appropriate name like "Rain Patterns, July". Once the background is visible again, it might look like this (again, just showing a little area):

The difference between this and the end result above is that I have rounded off the corners. Because the map is supposed to be showing a "likelihood" of rain, transition between levels should always cover the intermediate levels. Depending on the level of detail you want, you may skip this part altogether and adjust later on when we get to the actual climates.

One last thing that can be done, if you want to, is to delete all the parts of the "wetness" map that are over the sea.

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## groovey

It's amazing to me how you can work out all these things, you make it look so easy. 

I feel myself naturally inclined to this sort of information about planets, real or fictional, but it's frustrating because I can't get into it, it's too much deep and complex information for me, so when I try to, after a bit, my head gets fuzzy and then I just quit it because I'm unable to process further information anyway. So I'm taking it very slow, reading a bit from here and there, watching any documentaries I stumble upon about how the Earth works and such. I hope at some point everything fits into place in my brain and I can figure it out and apply it to a fantasy world map.

Anyway, I'm bookmarking this thread because I'm sure it'll be helpful to me at some point. Thanks a lot for taking the time to do this walk-through.

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## Ilanthar

Hey Pixie, you're clearly a perfectionist in your own way  :Wink:  My work consists a bit in scientific vulgarization, so, I find your work here very interesting and quite complete.

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## sangi39

I'm going to be very blunt about this, since I don't often get the chance in life to be blunt, but my reaction to this thread is simple...

Pixie, I think I love you  :Very Happy: 

Definitely a worthwhile addition and expansion to Geoff's work in the Climate Cookbook, especially in dealing with linking the various stages together (Geoff's work, as I found out in my own work, has its limitations, especially when it comes to Koppen stuff, but that's already been discussed). I'm really looking forward to seeing more of this and I may even have to start linking it in other forums if it continues on the way it does.

It's also made me realise that I should probably work a bit more on my altitude maps a bit more. Annoying I only really have mountain range peaks  :Razz:

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## Pixie

Thanks for the compliments but save them for the end of the thread or I may well leave it half done.  :Wink: 

In the meanwhile, if anyone is (has) tried this technique so far, I would like to know how difficult it was to apply and if there is anything unclear, overlooked, forgotten... This would be really helpful.
Cheers!

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## AlexSchacher

I attempted to use your ocean currents tutorial on my world map and posted my attempt in the thread "Another attempt at a world map" here in the regional maps subforum. 

I would link to it but i cant figure out how to do that using the tapatalk app, but when i get to my computer ill edit this and link it if i remember.

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## Pixie

> I posted my attempt in the thread "Another attempt at a world map" here in the regional maps subforum.


Just commented on it. It's very good.

As for this thread.. I realized my technique for devising a temperature map had too much happening in my head at the same time and isn't easy to translate into tutorial-like steps. I'm trying to figure out an alternative way. That's why I haven't posted the next step... It will come, though!  :Very Happy: 

EDIT.... I figured out a step by step way, will publish it soon - as soon as I find the time to write it down with illustrations.

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## Pixie

Back at this.. It took me a while to find a perfect system I could share (and it probably ain't perfect or that easy to follow, but I'm hopeful).
This is the first part of steps towards creating a mean-temperature map for the extreme months of July and January. Along with the wetness maps for these months, we will then be able to determine the most likely climate for each region.


Temperature has a lot of conflicting influences, so we aren't just adding layers like we did for rain. The technique is somewhat different. We first map where each kind of influence is a factor to take into account. Then we generate a temperature map as if the continent was flat and waterless. And then we start adapting it.

So, first thing is mapping what will factor in. Create separate layers for each of these influences:
- Maritime influence / July and January
- Continental influence
- Cold ocean currents / July and January
- Warm ocean currents / July and January
- High humidity / July and January
- Medium elevation
- High elevation
- Very high elevation
(Overall it's 12 layers).

We'll look at one at the time. 
1. Maritime influence: 
Select all your oceans, seas and reasonably sized lakes (magic wand tool is your friend here). Expand that selection a fair number of pixels. Now, make your layer with dominant winds visible (for the corresponding month) and adjust your selection. Prolong it inland where the winds blow onshore, make it shorter where winds blow away from the coast. Lastly, check your topography. Areas behind mountains don't get maritime influence, except if winds can blow around them.
Paint your resulting selection in solid white and hide the layer.
Repeat for the opposing month.


This is an example where I made the white layer 50% transparent so you can see how the wind affects it.


2. Continental influence. 
Select your land masses with the magic wand. Contract the selection a fair bit (in my 1000 pixels tall map, I contracted about 50 px). Check your topography and extend this selection to all areas cut away from the seas/lakes/oceans by mountain ranges.
Again paint in solid white (we'll always do this) and leave it.

3. Warm and cold currents, July and January.
All these four layers are done in the same way. Make winds and currents visible (for the appropriate month). Make a wide selection covering the arrows with the currents. Extend the selection in the direction of prevailing winds. Again, since this a maritime influence, the selection cannot pass over mountains, so check the topography before painting in plain solid white.


Taking winds and currents into account results in something along the lines of this (shown here is the area influenced by warm currents in july). 


4. High humidity
Use your rain patterns map. Make a selection encompassing all areas that are Very Wet or Wet. That's it, it's your high humidity zones, which you paint as before.

5. Elevation
We will cover three different elevation levels. Medium elevation is the selection encompassing everything above 1000m (roughly), High elevation covers areas above 2000/2500 m and Very high elevation will be for stuff above 5000m. These are aproximate levels, just use your judgement depending on your own elevation map.


Showing here is the area considered medium elevation (about 1000m high or above). As you can see this is quite a "tall" continent, and that will surely influence climate a lot...


Now, the influences are mapped. We will do the baseline temperature map which accounts only for solar radiation. Solar radiation depends mostly on the angle between the sun rays and the surface. In July, the Sun is stronger in the northen tropical line at 23º (equals the tilt of Earth, if you are doing a different tilt, adjust this); and in January same happens at 23º S.


Here's how I got this drawn:

1. First I defined a set of colors for "Very Hot", "Hot", "Warm", "Mild", "Cold", "Very Cold" and "Extremely Cold". 

2. Then I drew a small 2 px line, East-West, halfway between the tropical line and the equator using the Very Hot color.

3. Then I measured the height North Pole to South Pole, in pixels and divided that by eleven. This gave me the width of each of the areas. Then, starting with the line I had drawn, I just kept expanding the selection by the number of pixels needed.

The result was this baseline "radiative" map. Note that I didn't take into account the curving of the latitude lines in the map associated with the projection. I took this liberty because I am only using the center of the map. You may have to devise alternative ways to create the baseline temperature if your map has a different projection. The point is to have this "striped" effect, ranging from Cold to Very Hot and back to Extremely Cold.
The pole facing the sun will start at Cold, whilst the other one will be Extremely Cold. In this case, the map is for January, since it's Summer in the souther hemisphere (that's the pole facing the Sun).


Time to take a rest before the second half....

EDIT: some spelling and grammar corrected

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## Pixie

Now we start shaping those straight lines from the baseline map. Start by putting the baseline map under all the layers which map influences and make all those layers 60% visible (opacity).

We will deal with one influence at a time. They may curve the lines in either direction. As a general rule I make the influence curve a temperature boundary only half way to the next boundary. I hope you get what I mean with help from the ilustrated examples.

Right, so let's jump in. You can ignore topography, winds, rain, and what not. All it matters now is the temperature map and each of the influences. So, turn everything off, except the baseline radiation map and...

1. Maritime Influence
This is a milding influence, which means it turns areas closer to mild/warm temperatures. Which means, bend the boundaries in a way that turns some "Very Hot" area into "Hot" area and "Hot" into "Warm", and on the opposite side, make "Extremely Cold" into "Very Cold", and so forth until "Cold" turns to "Mild".


As you can see, I use a dummy/draft layer to write the new boundaries, then adjust the temperature map. You have some liberty adjusting those boundaries, just try to keep the same criteria throughout. 


2. Continental Influence
This is an extremes influence, basically working in the opposite direction to maritime influence. "Hot" turns to "Very Hot", "Warm" to "Hot" on the other end, "Cold" gets "Very Cold" and so forth. Mild is not affected.
Again, re-shape those boundaries like before.



In this particular case, you can see how the interior of this equatorial continent gets hotter. The original straight lines are disappearing already...


3. Cold/Warm currents
These have cooling or warming effects, obviously. However, they cannot take areas into extreme temperatures. Thus, they never influence an area into "Very Hot" or "Very Cold" into "Extremely Cold".


This is now showing the mean july temperatures after cold and warm currents are factored in. In the left side of the map I created a pocked of "Hot" in the middle of "Warm" as that area was under the influence of a warming factor and less than halfway to the next boundary - this can be done with any influence.



4. High humidity
This is a no-extremes effect. Water "soaks up" a lot of heat energy preventing temperatures from rising sharply and it also releases that heat energy should temperatures really drop. It changes every area closer to "Hot", "Warm" or "Mild". Areas already in these temperature range are not changed.
Keep reshaping the map. In this case, all the areas under this influence get affected, it's not a case of bending the boundary "half-way".


5. Medium Elevation
Well, the higher, the colder, that's a basic rule of thumb. Every temperature range will drop one level colder. However, compute this obeying the "only halfway to next boundary" rule... medium elevation isn't that high.


6. High Elevation and Very High elevation
On the other hand, these influences will make the temperature drop no matter at what latitude. Any area under this influence gets colder. I suggest you work this out from cold areas to warmer areas - if you do the other way around you will end up messing up the work.


..July   ..January
So this is the final result. After every factor is computed in, I zoomed in on the details that didn't look right (like spikes, right angles, etc) and adjusted them slightly to get a more "natural" result. Then I used the sea mask to delete the over-the-ocean-clutter and end up with a mean-temperatures map of the land only.
But this is it, as computed by the method I just detailed.

It's a very mild Winter for most of the land south of the equator apart from the highlands where it gets Very Cold even at the tropics, while the Summer on the north is Hot, but not extremely except in some pockets. In January, on the other hand, things are different, Summer is scorching inland south of the equator. The very tall plateau in the northern hemisphere, however, even if almost tropical, gets freezing temperatures.

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## groovey

So glad to see the tutorial growing.

I finally got the guts to try out after being done with tectonics but I've a silly question before starting. In one of the first posts you recommend using Hammer projection, but I see for example Akubra did his currents on equirectangular projection, which I prefer too. So does the projection affect the results significantly? I don't mind using Hammer though, if necessary, in fact I'll get a Hammer version of my map to have it ready just in case.

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## Pixie

No, the projection doesn't matter at all. All you need to do, whatever the projection, is follow the latitude lines.

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## Azélor

Yes but the latitudes are curved with the Hammer projection so you'd also need to curve your temperature zone (but the impact is minor if you only intend to make this continent)

 I would like to know if your using a particular climate classification for this? It would be good to know how hot is the ''Very Hot'' area. 

As a side note, your continent is small to have any real continental influence unless I'm missing something. Maybe there is but it's very small as you said in point 4.

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## Pixie

Thanks for the interest Azelor, it's good to know more people are reading and it's not just a 4/5 men show   :Very Happy: 




> Yes but the latitudes are curved with the Hammer projection so you'd also need to curve your temperature zone (but the impact is minor if you only intend to make this continent)


Indeed, I couldn't be bothered to curve my temperature zones since I was only using the center of the map. But, if I were to do it again, I would stick to equirectangular map
or make a "flat" image with the temperature zones and then project it using g.projector. In fact, that's a path worth exploring one of these days for continents at higher latitudes - playing around with non-equatorial projections.




> I would like to know if your using a particular climate classification for this? It would be good to know how hot is the ''Very Hot'' area.


Coming up soon. I started using the table from Geoff's web page, but it left out a lot of areas after using my system for rain and temperature. I have a revised table that covers more variety and I will post it soon. It relates directly to Koppen classification, although it still merges a few zones (less than Geoff does). I'm working on the last-but-not-least bits of that.





> As a side note, your continent is small to have any real continental influence unless I'm missing something. Maybe there is but it's very small as you said in point 4.


The southern portion is pretty massive. It's being so close to the equator that distorts the perception of area - but it's more than twice as big as Australia and about 1000 km wider than North America (the southern portion that is).

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## Azélor

Yea I'm reading it and also other threads but only answer from time to time. 




> The southern portion is pretty massive. It's being so close to the equator that distorts the perception of area - but it's more than twice as big as Australia and about 1000 km wider than North America (the southern portion that is).


Funny, because Hammer is supposed to prevent area distortion. But not the shape. Well, then it make sense. 

As a side note, I'm working on something on the Koppen climate. I'm trying to make it ''easier'' to understand or so I hope to. Because frankly, climates are complicated and the english wikipedia page is a mess.

----------


## Pixie

Well, Azelor, in that case, I am really really interested in reading what you have to say about my system (see the posts below). While the whole thing makes sense to me, I am not sure at all if I am missing important aspects or not.

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## Pixie

Reaching the final stage of all this work.

Now, we start to find out the actual climates. This is based on Koppen's classification, but somehwat limited, since we only have graphical information for the extremes. The result will always need some polishing and some reviewing, so you need to understand a little bit about climates. My advice is to follow the steps below and AFTERWARDS, compare your map with Koppen's Climate Classification, at Wikipedia, to see how it compares or with real life locations in similar geographical conditions.

So, let's put our maps to use. 
All it's needed now is the four maps we produced in the previous stages: 
- January and July Rain Patterns
- January and July Temperature

You are going to use the magic wand a lot, sometimes in "addictive mode" (enlarging a current selection with the area under one color), sometimes in "subtractive mode" (excluding an area under a given color from the current selection) and sometimes in "intercept mode". Identifying every bit of a particular climate is a matter of fitting a number of conditions, so I'll slowly go step-by-step for the first one:

1. HOT DESERT (BWh)
- at least one of the seasons as Warm/Hot/Very Hot
- no season as Cold/Very Cold
- both seasons dry

So I need to find the areas that "fit" all these three conditions: 
Looking at January Temperature map, I select all areas under dark red, red and orange (adding them).
Then I switch to July Temperature and I exclude the areas in light blue or colder from this selection.
Thirdly, using one rain pattern at a time, I intercepted the selection with the DRY areas.


This sequence of pictures shows the selection area getting smaller (the region under diagonal stripes), step by step.


The resulting area is painted in a solid color in a separate layer. Which I name after the climate - one climate per layer (easier to adjust later, if need be).
But it wasn't all done yet for this climate. I checked January being the warmest and July could be mild, I need to repeat the process for the remaining combinations. After which I got this result:


This is a very desertic land, I can see that now. It contains two huge deserts plus a few pockets and two small "coasts of death". But let's find out about the rest of the continent, there has to be some place where people can live and farm comfortably!

My choice of colors comes from this map.

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## Pixie

Word of warning: the following is a lengthy task. There are 4 variables (4 maps) and a lot of possible combinations. This will take time. The end result, however, is very rewarding, and I'll show you a neat map in the next post... for now, here's the list of climates possible and how to find them:

(Some climate classifications have been merged)

1. HOT DESERT (BWh)

- at least one of the seasons as Warm/Hot/Very Hot
- no season as Cold/Very Cold
- both seasons dry

2. COLD DESERT (BWk)
- at least one of the seasons as Mild/Cold/Very Cold
- not qualified as Hot Desert
- both seasons dry

3. TROPICAL MONSOON (Am)
- no season is below Warm
- one season Wet/Very wet and the other Low/Moderate

4. TROPICAL RAINFOREST (Af)
- no season is below Warm
- rain Moderate or above in both seasons
- not qualified as tropical monsoon

5. SAVANNA (Aw)
- no season is below Warm
- one season Very Wet/Wet/Moderate and the other Dry
(OR Moderate and then Low)

6. HOT STEPPE (Bsh)
- no season is below Mild
- both seasons are Low or one is Low and the other is Dry

7. COLD STEPPE (Bsk)
- both seasons are Low or one is Low and the other is Dry
- colder season is Cold
OR
- colder season is Very Cold and warmer season is Warm or above

8. MEDITERRANEAN (Csa)
- one season Hot/Warm and one Mild
- warmer season is Dry/Low and colder season is Wet/Moderate

9. COLD MEDITERRANEAN (Csb/Csc)
- one season is Hot/Warm/Mild and one is Cold
- warmer season is Dry/Low and colder season is Wet/Moderate

10. TEMPERATE MONSOON (Cwa)
- one season is Hot/Warm and one is Mild
- warmer seaon is Very Wet/Wet/Moderate and colder is Dry/Low

11. TEMPERATE HIGHLAND OR SUBTROPICAL (Cwb/Cwc)
- one season is Hot/Warm/Mild and one is Cold
- warmer season is Very Wet/Wet/Moderate and colder is Dry/Low

12. HUMID SUBTROPICAL (Cfa)
- one season is Hot/Warm and one is Mild
- warmer season is Very Wet to Moderate and colder is Moderate/Wet

13. MARITIME TEMPERATE (Cfb)
- one season is Warm/Mild and one is Cold
- both seasons are Moderate/Wet/Very Wet (or 
- not qualified as Humid Subtropical

14. MARITIME SUBPOLAR (Cfc)
- one season is Warm/Mild and one is Very Cold/Extremely cold
- both seasons are Moderate or above

14. MANCHURIAN (Dwa/Dwb)
- warmer season is Hot/Warm and colder season is Very Cold
- rain is Very Wet/Wet/Moderate in warm season and Dry in cold season

15. LAURENTIAN (Dfa/Dfb)
- warmer season is Hot/Warm and colder season is Very Cold
- rain is Wet/Moderate in cold season and Moderate/Low in warmer season

16. CONTINENTAL HIGHLAND (Dsa/Dsb)
- warmer season is Hot/Warm and colder season is Very Cold
- rain is Dry/Low in colder season and Moderate/Wet in warmer season

17. TAIGA (Dfc/Dsc/Dwc)
- warmer season is Warm/Mild and colder season is Very Cold/Extremely Cold
- not qualified as Cold Steppe or any other D-type climate

18. TUNDRA (ET)
- one of the seasons is Cold and the other one is colder

19. ICE CAP (EF)
- temperature is always Very Cold or Extremely Cold

EDIT 1: fixed/revised some "rules" for D climates.

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## Pixie

So, you went through all the climates and the map looks a mess (or not). Well, climates can be a mess, and the magic wand may not select some pixels, and you may have overlooked some combinations - the remaining is to be done by hand.

And we can start by the following
- there is probably an area very close to the equator that appears to be desert, between areas of savanna or monsoon... Well, it is savanna or monsoon! it's the rainy season in that region that doesn't match january or july (the ITCZ passes through in a different month, in its north-sound annual movement), so it slipped right under out radar.
- in some parts, a transition climate may not be appearing (like tropical monsoon between rainforest and savanna, hot steppe between hot desert and mediterranean, cold steppe between cold desert and continental, etc), add a strip of such climate manually and delete what was there before.

Then, you need to find out bits that aren't colored in any particular color and find the best fit manually (comparing with available information on Koppen classification, like I said before).

Thirdly, time to merge it all together and make it final. But I recommend you duplicate all the layers and simply merge the copies, just to be safe. Once this is done, you can smooth boundaries between regions, make very small micro-climate regions disappear if they are cluttering the map too much, etc.

After some work, including adding a key and a title (work-in-progress, still), this is my end result for the continent of Palamb:

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## Naima

Can u type in also a real wprld sampleof ur climatic zones prototypes? For example cold desert is like Gobi or Atacama?

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## Pixie

> Can u type in also a real wprld sampleof ur climatic zones prototypes? For example cold desert is like Gobi or Atacama?


I don't know. Honestly, I think it depends on the location and there was no way it could get that detailed. Read through the wikipedia page on Koppen's Climate Classification, it helps.

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## Azélor

I will comment from the beginning:

I still have no clear idea of your temperature classification but I'm going to take a guess:
extreme is below -38, very cold is below -10, cold is below 0, cool 0-10, mild 10-18, warm 18-22 ?, hot 22-32, very hot is over 32 degree Celsius 


*BSh and BSk:* small detail but it's S and not s, otherwise it mean summer dry 
these two climates can have a rainy season, some places could receive up to around 200mm of rain in a month because they are subject to the monsoon (mostly the hot one). Large parts of the steppes in Africa and Eastern Asia are affected. Examples include Niamey and Hohhot. 

*BSk* : is usually found at higher altitude than the hot desert 

Dont forget that : (I know it's pretty complicated!)

B. Dry climate: Annual evaporation is greater than precipitation (also called potential evotraspiration). To determine whether a location has an arid climate, the precipitation threshold must first be determined. The threshold value (in millimetres) is determined as:
      	If less than 30% of annual precipitation occurs in the summer : Annual precipitation (mm) < 20 × average annual temperature (°C)
      	If more than 70 % of annual precipitation occurs in the summer: Annual precipitation (mm) < 20 × average annual temperature + 280 
      	Else : Annual precipitation (mm) < 20 × average annual temperature + 140
o	If annual precipitation is  < 50 % of the threshold = BW: desert climate
      o	If annual precipitation is between 50 and 100 % = BS: steppe climate
So the steppe climates can be more or less rainy if the evaporation is very high too. The same principle stand for colder climates too. They receive much less rain than hot climates but are still considered wet because the evaporation is much lower. 

(detail) Also, according to the classification, it's possible to have cold winters in BSh as long as the average yearly temp are high enough. Rare but possible

(detail) BWn: it's an additional class for desert near water that have a small temperature variation like Namibia. I was considering incorporating it

*
Csb:* monthly temperature never go over 22, so it's not hot and not cold either because it never go below 0 (monthly)
I just like to specify that Csc form usually at higher altitudes at it's not very common

*Cwb/Cwc:*  monthly temperature never go over 22, so it's not hot and it's even colder for Cwc, they are located at higher altitudes

*Cfb*: it pretty sure that the temperature rarely go under 0. And what do you mean by very wet ?

*Cfc:* : it's hard to say because only a few places are said to have this climate. Like Reykjavik: the temperature difference are small and winters are cool around 0 degree. 

*D climates*: if I have the temperature right for the extreme cold, it should only be applied with : Dfd, Dwd, Dsd and the other colder climates. I tried to find other climates in the D group with winter months under -38 but I could not. 

*Dfa,Dfb*: you inversed the summer and winter precipitations.

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## Azélor

I admit that it's like a puzzle, there is a lot of elements you need to think at the same time. But even so, a puzzle always have pieces that have similarities and that you need to put one next to the other.

I'll try to take a look at the map but do you have a detailed precipitation map ?

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## Pixie

Thanks for your time, Azelor. You've pointed out some important stuff, namely, that I am ignoring the interaction between temperature and "wetness" when considering how dry is a climate. I think the desert/steppe/continental "gradient" will have to be a little reviewed. 

The point of this whole system, however, is to skip numbers - this is not because of laziness, but because there are so many "educated guesses" and approximations when it comes to a fictional planet-system that the uncertainty of any number is absurd. I mean, what's the point of saying a given place has a mean temperature of 25 ºC if the margin for such figure is.. say.. 30%. So, that's the rationale behind a fully graphical method, just to explain myself. Of course, you can throw a guess about what exactly "Very Hot", "Hot" or whatever means. I can agree with your guess without second thoughts.
I also want to make this tutorial easy enough for those without a science background - as much as that is possible - and that is why I am trying to define clear and easy to follow rules. Even to the point where some accuracy is lost. I'm not sure how this balance will work out.

Now, as for your valuable comments.




> *BSh and BSk:* small detail but it's S and not s, otherwise it mean summer dry 
> these two climates can have a rainy season, some places could receive up to around 200mm of rain in a month because they are subject to the monsoon (mostly the hot one). Large parts of the steppes in Africa and Eastern Asia are affected. Examples include Niamey and Hohhot.


So, I will probably have to review some of the combinations. Say, if a region is Very Hot/Hot in a season and Low in wetness, that roughly equates to "Dry" - and it would still be desert. Do you agree with this generalization?




> *BSk* : is usually found at higher altitude than the hot desert 
> 
> Dont forget that : (I know it's pretty complicated!)
> 
> B. Dry climate: Annual evaporation is greater than precipitation (also called potential evotraspiration). To determine whether a location has an arid climate, the precipitation threshold must first be determined. The threshold value (in millimetres) is determined as:
>       	If less than 30% of annual precipitation occurs in the summer : Annual precipitation (mm) < 20 × average annual temperature (°C)
>       	If more than 70 % of annual precipitation occurs in the summer: Annual precipitation (mm) < 20 × average annual temperature + 280 
>       	Else : Annual precipitation (mm) < 20 × average annual temperature + 140
> o	If annual precipitation is  < 50 % of the threshold = BW: desert climate
>       o	If annual precipitation is between 50 and 100 % = BS: steppe climate


Altitude is already factored in as one determines wetness maps and temperature maps, so Cold Steppes should appear naturally when a Hot Steppe region is in altitude (and it does in my tests). As for the numbers, I am aware of those, but as I explained I don't think I can bring formulas to this system (Geoff's Cookbook avoided it too).




> So the steppe climates can be more or less rainy if the evaporation is very high too. The same principle stand for colder climates too. They receive much less rain than hot climates but are still considered wet because the evaporation is much lower.


As I said, I'll review where some of the combinations fall into, namely between cold steppe and continental (C's and D's) and between hot steppe and mediterranean.




> (detail) Also, according to the classification, it's possible to have cold winters in BSh as long as the average yearly temp are high enough. Rare but possible
> 
> (detail) BWn: it's an additional class for desert near water that have a small temperature variation like Namibia. I was considering incorporating it


Thanks for these details. I didn't know BWn classification. As for the detail about the BSh, if we don't mention it in "the rules", a piece of hot steppe will be classified as cold steppe, if we mention it, the rule gets more complicated... a choice affecting balance between accuracy and friendliness...





> *Csb:* monthly temperature never go over 22, so it's not hot and not cold either because it never go below 0 (monthly)
> I just like to specify that Csc form usually at higher altitudes at it's not very common


This was definitely a choice I made towards friendliness. Merging Csb and Csc allowed for Cold winters. In my tests this covered highlands close to Mediterranean proper (Csa) more than areas immediately poleward of Csa, but it might be a peculiarity of the continent I used. That's why I will have to try this system in different continents.




> *Cwb/Cwc:*  monthly temperature never go over 22, so it's not hot and it's even colder for Cwc, they are located at higher altitudes


I get your point but, the thing is, how would you classify a region with Hot summers (over 22) and Cold winters, with sufficient wetness (that's "moderate" or above in the current rules). However, I see Hot+VeryWet Summers with Cold/LowRain Winters falling a bit awkwardly into Cwb - can you find a better fit?




> *D climates*: if I have the temperature right for the extreme cold, it should only be applied with : Dfd, Dwd, Dsd and the other colder climates. I tried to find other climates in the D group with winter months under -38 but I could not.


So, the consequence of this is that all regions with an Extreme Cold temperature should strictly be Taiga or Tundra?




> *Dfa,Dfb*: you inversed the summer and winter precipitations.


Thanks... fixed! (wish all fixes were these simple  :Wink: 

As I said, thank you for the help. There's a few questions in the middle of my replies, did you spot them? As for temperature and rain charts, you can see them in a previous post, I have the four side by side when explaining how to "find climate zones".

----------


## Azélor

You’re probably right, we are just amateur for the most part so using real numbers will only make the process more complicated for a little gain in precision. And most people won’t notice it. 
Obviously, if I’m trying to make it simpler, I’m heading in the wrong direction !





> So, I will probably have to review some of the combinations. Say, if a region is Very Hot/Hot in a season and Low in wetness, that roughly equates to "Dry" - and it would still be desert. Do you agree with this generalization?


I’m not sure I understand the question. My main point was to say that in Koppen classification ‘’S’’ and ‘’s’’ are two different things. 

S: second letter that indicates a steppe and only usable with first letter B
s: also second letter but mean that the summer is dry. Maybe it’s possible to use it with B but for some reasons, it does not apply to deserts BW (because it rarely rain anyway) or steppes BS. 

Very hot and dry season = desert or steppe

Since monsoon only occurs in summer the very hot season, it’s impossible to have a monsoonal climate with a hot and dry summer but wet winter. The only that comes to mind is AS but the dry season is only considered dry because the wet season is really rainy. So it’s not that dry.   

So it’s either a hot desert or it could also be a hot semi-arid. He does not have to be subject to the monsoon. And if it’s not affected by monsoon, the wet season is also the coldest. 
So it means there are two types of hot arid climates, with different precipitation pattern, nice…




> So, the consequence of this is that all regions with an Extreme Cold temperature should strictly be Taiga or Tundra?


I guess so. Extreme would not be extreme if it applied to a large part of the world.
This is about the coldest I've found in Dfc, Dwc, Dsc  Krasnoyarsk Krai - Wikipedia, the free encyclopedia
Don't forget that the number are based on the monthly average. For example, it's possible to have a temperature of -50 in Manitoba (Dfb) or Mongolia but that's way below their average. 




> I get your point but, the thing is, how would you classify a region with Hot summers (over 22) and Cold winters, with sufficient wetness (that's "moderate" or above in the current rules). However, I see Hot+VeryWet Summers with Cold/LowRain Winters falling a bit awkwardly into Cwb - can you find a better fit?


Well to start of, there is probably just one place on Earth with a Cwc climate based on the wiki map. Can you find it just by looking at the map ? 
It's possible to have it cover a larger area in a fantasy map but it won't be much. But you question is how to classify this climate ? :

Summer: Hot, very wet
Winter : Cold, dry

Dwa maybe ? It's affected by the monsoon but I'm not sure it's wet enough




> As for temperature and rain charts, you can see them in a previous post, I have the four side by side when explaining how to "find climate zones".


Really? I mean the 2 central parts are really dry. But I can't say if you did something wrong with the precipitation pattern because that part is really hard for me.

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## vorropohaiah

now this is my kind of thread - just leaving a comment here to make sure im subscribed and to say good work! wish i had the paience to do this with my own world

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## Pixie

Thanks for support, vorropaiah  :Wink: 

Now, let's keep the discussion going - the "rules" to identify climate zones are far from finished.




> Im not sure I understand the question. My main point was to say that in Koppen classification S and s are two different things. 
> 
> Very hot and dry season = desert or steppe


I got that, Azelor, my point is about the rule-set I am devising. 
In it, a region that gets rain ("Low" level, but still, different than "Dry" level) in any of the seasons doesn't get classified as Desert but as Steppe.
From our discussion, I take it that a region which has a "Low level" of rain but during a "Very Hot" or "Hot" season, should still be qualify as Desert.

Or (a different solution I am also considering).... once the temperature map is finished, use it to reduce the rain level in the Wetness maps in the areas where seasonal mean temperature is "Very Hot". Maybe this would yield the same result and be easier / more graphical.





> Since monsoon only occurs in summer the very hot season, its impossible to have a monsoonal climate with a hot and dry summer but wet winter. The only that comes to mind is AS but the dry season is only considered dry because the wet season is really rainy. So its not that dry.   
> 
> So its either a hot desert or it could also be a hot semi-arid. He does not have to be subject to the monsoon. And if its not affected by monsoon, the wet season is also the coldest. 
> So it means there are two types of hot arid climates, with different precipitation pattern, nice


I see what you mean. I should split my current rules for Am between proper monsoon and chaparral-style climate (long dry summer plus a really wet but short season).




> Well to start of, there is probably just one place on Earth with a Cwc climate based on the wiki map. Can you find it just by looking at the map ? 
> It's possible to have it cover a larger area in a fantasy map but it won't be much. But you question is how to classify this climate ? :
> 
> Summer: Hot, very wet
> Winter : Cold, dry
> 
> Dwa maybe ? It's affected by the monsoon but I'm not sure it's wet enough


Dwa it is!  :Smile: 




> Really? I mean the 2 central parts are really dry. But I can't say if you did something wrong with the precipitation pattern because that part is really hard for me.


Yeah, I didn't anticipate it either. But (you can see the detailed, but already slightly outdated heightmap in here), both inland cores (north of the equator and south of the equator) are in the rain shadows of very large mountainranges and fall into desert latitudes. And I had a industrialized nation in it at start.... (they're dead now)

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## Corvus Marinus

I'm really happy to see that you've updated this. I'm moving to the Republic of Georgia in August (for a short-term teaching job), and so am at present very busy getting ready for that, but I look forward to implementing your latest instructions whenever I find time. Keep up the good work!

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## Azélor

I need to go back at what I said about Cwb/Cwc:

They are indeed different but the simplifications you made abolishes these differences since they fit in the same temperature categories. The only difference is : Cwc is colder (but that should be obvious)
I suggest that you just ignore it. 

but here's the details in case your curious:

Cwb
•	Average temperature of the 3 coldest months  between 0 °C and 18 °C
•	Average temperature of the 4 hottest months between 10°C and 22 °C


Cwc:
•	Average temperature of the 3 coldest months  between 0 °C and 18 °C
•	Average temperature of the 3 hottest months between 10°C and 22 °C
•	No more than 3 months with average temperature > 10 °C

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## Pixie

I think we are now at the same page, Azelor, concerning simplifications.

At present, Corvus Marinus is in the latest stage of this scheme of work, and ascanius and I are testing it as well with this map.

I also want to further test it with real-earth map in order to compare with real-earth climate zones, but for some reason (the plain fear of realizing that I have it all wrong) I didn't start yet.

Once all this testing and the fine-tuning I am doing with you is completed, this can become a real tutorial (as in a pdf at the tutorials section). Do you agree?

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## Azélor

Yes it would be a great tutorial !

also, you can check here and give me your opinion about my... simplification:
http://www.cartographersguild.com/re...i-hope-so.html

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## Azélor

So, what I think of your climate map now that my document is done... It looks pretty good but the sheer number of elements to consider open some room for choices, and mistakes.

I have some points that I would like to discuss:

1- The eastern hot steppe seems really dry for a place close to the equator that faces the major winds from the ocean. The mountains are not that high, so I think it's too dry, except for the southern tip. 

2- The eastern side of the cold highland desert should be really wet, probably the wettest place on the map. Not only have they received water like the nearby tropical forest but also because of the orographic lift. It reminds me of the region near Nepal, north-east India. 

3- it’s unlikely that you can have a D climate on that map except maybe on the southern part of the continent (the cold steppe plateau) maybe but not on an island. The climate is much more temperate and less extreme because it’s surrounded by water. It’s probably Cfc 

Lastly, like I said to Corvus, Mediterranean climates are close to the sea. they could still be located not too far inland but one of yours if hidden behind a mountain range.


Overall it's pretty good!

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## sangi39

I've been largely inactive for the last two months* but looking at this thread, Azelor's recent thread on Koppen climate zones and the work done by several users regarding tectonics, I might have to restart my work on Yantas. As much as I like the current look, I feel like I kind of rushed the tectonic stage and I never really dealt well with Geoff's climate tutorial.

*I've recently separated from my wife (mutually), moved back in with my mum and brother, blah blah blah) and gotten so tired of doing almost anything (needed to see a counsellor about stuff). Hectic couple of months really  :Razz:

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## Naima

Hi  have a question on Climates ... 

Are they regulated only by temperature and rainfall? SO can I find a tropical rainforest in northern area if there are right conditions? or an alpine tundra at equator if high enough?

Can elevation altitude be considered for a relative "coldness" and lati

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## Azélor

Yes the Koppen classification mainly use these two to classify the climates. But others might use vegetation or something else to classify. 
But rainfall depend on wind direction. this mean that some climates always appear at specific places. For example: Mediterranean climates are always on the west coast near a body of water. 

Alpine tundra is still a tundra: The temperature drop by about 5,5°C for each 1000m. So if you consider that the average yearly temperature at the equator is around 25 to 35 °C then altitude would be around 4500m and 6400m or maybe more than that depending on the surroundings. But if it's much higher than that the climate become too cold to be considered a tundra and become land of eternal ice.

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## ascanius

The one thing I'm having trouble understanding is why the majority of rainfall seems to occur during the summer and the dry seasons seem to be during the winter and not the summer.  The only thing I can come up with to explain this is that the rain maps are not for summer and winter exactly but for fall and spring.  With the summer rain map showing fall and winter shows spring.  If this is true than wouldn't this alter how we are getting our climates on the map.

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## Naima

I wonder how coudl Mongolia be a tropical land in the miocene - pliocene , it didn't seem to be that much lower latitude .

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## Azélor

> The one thing I'm having trouble understanding is why the majority of rainfall seems to occur during the summer and the dry seasons seem to be during the winter and not the summer.  The only thing I can come up with to explain this is that the rain maps are not for summer and winter exactly but for fall and spring.  With the summer rain map showing fall and winter shows spring.  If this is true than wouldn't this alter how we are getting our climates on the map.


For different reasons:

areas subject to monsoon receive a lot of rain in the summer. Monsoon always occur in summer because it's the result of high temperature over the land and lower temperature over the sea... This only happens in summer
more or less : Am,Aw, Cfa, Cwa, Cwb, Dwa, Dwb and sometimes: BSh and possibly Af
some of these place like southern USA are not officially recognized as having a monsoon but they have the same precipitation pattern 

The other thing to consider is that cold air contain less moisture than hot air = less rain when it's cold. And also less evaporation. 

A lot of the temperate climates receive rain all year long. Mainly: Af, Cfb, Cfc, Cfa (sometimes), Dfa, Dfb.




Finally, this may not be the perfect answer but it is probably because not all climates have the same number of season. Some have 4, some have 2, and some have only 1 because there is little variation over the course of the year.

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## Pixie

So, there is a dramatic difference between the "rain pattern" in a region and the "available humidity". This is because of the effect of temperature on evaporation as discussed above.

So I used this key (already mentioned in Azelor's "sister thread")

*Lower precipitation than evaporation (ARID seasons)*
 Very Hot + Moderate/Low/Dry
 Hot + Low/Dry
 Warm + Dry
 Mild + Dry

*Roughly equal precipitation to evaporation (SEMI-ARID seasons)*
 Very Hot + Wet
 Hot + Moderate
 Warm + Low
 Mild + Low
 Cold + Dry
 Very Cold + Dry

*Higher precipitation than evaporation (HUMID seasons)*
 All remaining combos

Palamb's _humidity maps_ result in this (yellow is arid, lime-green is semi-arid and blue is humid):

 - january

 - july

This definitely changes things, but the process to work it out is still blurry in my head. So far, my only plan is a huge table, covering all possible combinations - not ideal.

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## Azélor

Something is wrong, because it's pretty dry compared to Africa or South America. They should have similar climates.

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## Pixie

I'll try two changes and share the result:

1. making coastal rains get further inland where possible, recalculate rain patterns and on from there

2. trying a little lower threshold for "arid" seasons and see how that works

Anyhow, as we discussed before, this particular continent has serious mountain ranges blocking nearly all westward winds coming from the ocean and that should have significant effects, so maybe it is just what it is.

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## lishamatish

Just wanted to pop in and say thank you so much for the tutorial  :Smile: 
I thought maybe I was going crazy wanting to get into so much detail and poring over atlases and encyclopaedias was sending me a bit loopy so I really appreciate the information here!

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## Naima

Can I follow this tutorial or was it changed ?

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## Azélor

yes you can follow it but the last part, the step 7 is messed up because of me  :Smile:

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## AesirKnight

I'm just chiming in to say this is fantastic. I've been out of worldbuilding for a long time, but recently got the itch again, and have been wanting to make something realistic and detailed. This is great, thank you!

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## J.Edward

This is a great and informative thread. Pixie and Azelor - appreciate all this.  :Wink: 
[must subscribe to this.]

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## Naima

I am having problems actually understanding what exactly I shoudl delete here :




> 1. baseline rain
> All the layers will be colored with one color only. I use a not-too-bright blue, RGB:100.100.150. Brighter colors will make the end result hard to read.
> For the baseline rain you just select one very big area (the whole map if you want) and bucket-fill it with this color. Then toggle off the layer and toggle on atmospheric features. Make a selection (using the lasso tool) around the high pressure centers (stretch it further east and west than the actual centers drawn before). Don't loose the selection, toggle off that layer and toggle on the dominant winds. Adding to the selection choose coasts where the wind direction is offshore and the areas behind mountains that winds cross (normally called the rain shadows of those mountains). Still, keep the selection. Toggle off the winds. Go back to the baseline rain layer and just press delete. Now your initial baseline rain has gaps big and small. Toggle it off again so you can clearly see the land. Make a selection encompassing all land that is far away from the coast or protected from coastal influence by mountains. Back to the baseline rain layer and delete that as well. The end result, for me, was this:

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## Azélor

I think it is :

layers
-atmospheric features : the high pressure centers (stretch it further east and west than the actual centers drawn before)
- dominant winds: coasts where the wind direction is offshore and the areas behind mountains that winds cross (normally called the rain shadows of those mountains)

delete these areas of the baseline rain layer

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## Naima

But that what means practically? That offshore windy coasts and high pressure centers get no rain?

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## Azélor

That part of the tutorial is confusing because he is not showing the final results.

The way I understand it, these will get no rain with the baseline rain layer. 
But they might receive rain with the other layers.

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## Naima

Yes I cant get past. That. Portion of the tutorial , also because I am using the base ft output to start from wich is based on the formula calculations that are relative to temperatures and rainfall for the whole planet.

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## Naima

I am starting to think that its too complicate to really be able to implement for me , to be precise I woudl need at least a month full time on that when perhaps a nice program could do it faster and implement all that tutorial in a click ...

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## Azélor

Waldronate once told me :




> Be sure to take FT's rainfall and temperature results (and the climate information derived from them) with a pound of salt. FT doesn't model any kind of water or air transport (and their associated heat and rainfall), so the results are not even close to "realistic".
> 
> My hope in providing the rainfall, temperature, and climate tools was to allow users to paint them in as they needed, but it seems that very few users attempt anything like that.
> 
> And the Gaia coloring is completely ad hoc, based on nothing at all (the rainfall and temperature adjustments have asbolutely no impact on that particualr shader). If there's one feature that I would have left out of FT, it's the Gaia shader.

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## Azélor

> I am starting to think that its too complicate to really be able to implement for me , to be precise I would need at least a month full time on that when perhaps a nice program could do it faster and implement all that tutorial in a click ...


I finished Pixie's tutorial for the whole CWBP2 and it took me a couple of hours. I still need to make some corrections. Still, it gives a good idea of what the weather is around the world. 


Now I do have some comment/question about the tutorial itself.

1-It is not clear if the cold/hot currents use the absolute or relative temperature. Some cold current are hotter than ''lateral'' current therefore I applied the cold oceanic effect to some mild currents. 

2- The currents at the poles are moving westward yes? As I understand it, there is a loop that starts at the equator flowing westward then poleward, eastward at the 45th latitudes, and then back to the equator. But I think there is another loop in the north starting at the 45th.  It flows counter clock wise. Lastly, it is said that Antarctica has a counter current flowing eastward close to the coast but I cant find a lot of informations on that.

3- Winds in the polar front move to the east. They are also known as the Westerlies. While Im not sure how the winds behave at the Poles (high pressure area) I think the winds should converge to the Polar front. 

4-Wetness map: As I understand it, all the wettest categories fall into the same category and need to be fused together. In total, there is only 5 level of rain left. It makes sense because the impact on the climate between 3000mm or 6000mm is not that large in comparison to the difference between 300mm and 600mm, for example. 

5-The maritime influence maps are almost identical in January and July or I did something wrong? I think it's because the area affected is small.

6-Precipitation problem? Im not sure how far the inland precipitations should go. I was just wondering if my dry zones are really supposed to be dry.  

7- When you say  Halfway through the other category it is based on the original layer or the modified one? I think that multiple effects should stack but each effect added has a weaker impact. 


8-The temperature for high mountains seems way off, in my case. Mt Everest would be without snow acceding to the tutorial. I have a mountains range with similar characteristics as the Himalayas and the temperatures in summer go between 18 and 22... So we need colder mountains. I thinks the need to be able to have high mountains (over 6000 m) with temperature always below 0 Celsius at the tropics and maybe closer to the equator. As stated here: Snow line - Wikipedia, the free encyclopedia

My elevation map has 6 levels of altitudes (but the last one is marginal):

1: 0-500m
2:  500-1000m, these two are at the same temperature but:

3: 1000-2000m: lower the temperature like you did in the tutorial
4: 2000-4000 (high latitude): lower the temperature by one full category
5: 4000+ (very high): lower by 2 categories
And another one just for the highest summits: 6000 +: lower by another 2 categories
That way, even if there is a hot climate at the bottom, the summits of the high mountains will have snow all year long. Unless you are at the equator where 6000m is not always high enough to keep the snow.

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## Iggy

I have assembled Pixie's instructions into a single document and exported it as a PDF file for personal use. I could post it here but I would rather hear Pixie's approval of it first.

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## Adversary

This is an awesome tutorial! It reminds me of many things I have forgotten from my meteorology class (which oddly enough has nothing to do with meteors  :Smile:  ). The main points I love have to do with the climates and ocean currents. There are a couple of assumptions that I can make about your planet from this tutorial. First you planet has an axial tilt of about 10-30 degrees. Less than that and you would not have noticeable seasons, more than that and the seasonal changes would be extreme. Second, your planet rotates counterclockwise as viewed from above (North). If it rotated the other direction the wind rotations would switch.

I didn't see your jet-streams. You should have one for each latitude zone, each moving from west to east. These will drive your temperature, weather and general climate. Look at North America. The important jet stream runs generally from Washington state to Maine. In the winter the jet stream dips into the central United States bringing cold air from Canada. This last year the jet stream looped further south than usual and Atlanta, Ga ended up with a major snow storm.

In your world the Jet stream will help explain your weather. If the jet stream runs north of your continent the predominant surface winds will come from the west will and the wet air from the ocean will make the north west coast more humid. The air will dry as it moves across the continent, especially in the shadow of mountains. As the jet stream moves south with winter, the wet zone will move south with it possibly causing monsoon rains. The east coast will not gain much benefit from eastern ocean winds in the winter and will mostly get drier air from the west. The southern half of the continent should have similar weather patterns with opposing seasons. Think about the jet streams remaining in place as the planet tilts under it. In winter (north continent) the jet streams all move south and north in the summer.

Another point is that weather will not cross the equator. More correctly, the weather will not cross the line where the sun is directly overhead. This area will obviously shift with the seasons; south in the winter, north in the summer. Where the sun is directly overhead the planet will have longer days, which heat the ground (and water) more so the air rises. North of the equator the air goes north and south of the equator it moves south. This rising air will act as a barrier to weather patterns. That is why hurricanes (or typhoons) never cross the equator. They tend to wander north, north of the equator and south to the south of it. Of course in the mountains the weather will be cooler (think of Equador) creating micro climates.

I hope I did not muddy the waters. This is a very complex subject and if it was perfectly understood the weatherman would always be right.  :Smile:

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## ltan

Iggy: If Pixie is ok with it, I would like to have a PDF version!

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## vorropohaiah

> Iggy: If Pixie is ok with it, I would like to have a PDF version!


same here!

(and while were on the subject, does anyone know where to find the climate cookbook nowadays?)

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## ltan

vorrophaiah: I took a trip into the Internet Archives and dug up this link: 19th of  June, 2013

If no one else does it, I will work on converting it to PDF if that is wanted.


Edit:  DONE!

The formatting was coded nicely so all I had to do was save in PDF...

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## Azélor

I think I should add my own contribution here : http://worldbuilding.stackexchange.com/a/1395/147
There are some topics that we haven't really covered yet: Jet stream, El Niño, deep ocean circulation, fantasy climates ? 

Maybe I should make my own thread ?

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## su_liam

Thank you, Itan! I've been looking around for that site. In desperation, I finally got permission from Geoff Eddy to post the worldbuilding and climate cookbook pages in my blog's goodies. The formatting was a little funky, but at least I could refer to the information and charts.

The Wayback Machine allowed me to pull up his other, mostly more linguistically-oriented stuff like the sound change applier which I hadn't kept on my hard drive. I am now slurping it up.
Did I remember to thank you

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## Azélor

Pixie, we're going (or just me) to make an automated process, possibly with photoshop actions. I don't know much about it yet but it can record all the step as I do them. So we can create an automated technique without having to code endless lines of gibberish. One thing I need to figure out is what exact actions should be done. It's mostly selecting layers, add/intersecting/exclude them with other layers and ''painting'' the results on a final or temporary layer. 

I already have the workflow for the section on temperatures but now I'm at the part with the rainfall. As I already mentioned, figuring out what places are supposed to be dry require the combination of temperatures and precipitations. 


There is 3 important steps to do:

1- find the temperature zones: Ice, tundra. A, B (hot or cold), C (Ca,Cb, Cc optional), D (Da, Db, Dc, Dd optional), so far, it's the easiest part because it's the least subjective
2- find the pluviometric regimes: winter dry, summer dry, or else it's always wet (f). That part is more complicated.  I decided to change the regime coverage based on the fact that winter dry climate have very dry winters, much drir than summer are in summer dry climates. And winter dry usually have very wet summers. But all this suppose that the starting rainfall categories make sense. 
3- find the humidity level, between humid, semi-arid and arid. 

This is actually the most complicated part, because there are a lot of possibilities. I did try to estimate what areas should be dry based on the temperature and precipitation but I'm not sure it's good.

We can ignore the ice and tundra here, they are black.
Ignore the 2 colours of blue, they are both for the A. But light blue is Da
From the 25 possibilities, 13 from the top left are always wet and can be cleared. Or more specifically, they can be selected and put in a separate layer. 
We see that, the hottest climate is in the top left of every section. it's the square that is the most likely to be dry with the same precipitation as the other colder climates. As precipitation get lower, all the section gradually becomes more arid until it's almost all desert except for the coldest areas. 

Process example: select a humidity layer (humid), select a pluviometric regime (w), select a temperature zone (Ca) 
the intersection of the 3 meta layers should give us the Cwa climate. 


Here the image I'm using as a guide. Does it make sense?

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## groovey

Hi again Guild! Azelor, if you managed to automate the process of figuring out climate you would have to be made the King of this place. I hope you do manage. I could be a tester once you have it, since mine is still pending an updated climate map and I've just recently started to mess up with my project again.

So best wishes for your work.

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## vorropohaiah

i cant really understand the image, though i think the possibility of a PS action tantalizing, though i cant really see how you could apply something like this to an action. Looking forward to seeing more about this (id love to set it out on my own world too)

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## Alphast

That's some serious background work...

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## Azélor

I can confirm that it's possible to automate some parts of the process with actions, most notably the selecting and comparison of temperature and precipitation layers (step 7). It could be possible to automate the other steps but with photoshop it's very hard.

I'm also planning to make my own tutorial but it's generally an improvement of Pixie's tutorial. I added more clarifications to avoid mistakes or randomness and added some clearer parameters set be recreating the climates of Earth. 

The method will have more temperature categories but they are mostly for the extremes, it doesn't make it more complicated.

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## MrSquiffy

Hi there. Apologies for necro'ing a two-year-old thread, but I've been following this guide quite rigorously in making my own world, and I've got a few questions about the temperature mapping, as it's causing me some degree of confusion. Any help or clarity on the situation would be greatly appreciated.

1. With the humidity layer, the guide states to shift the temperatures towards 'hot' 'warm' or 'mild', and to ignore areas already in those zones. How are you able to get to 'warm' following this system, if it's between hot and mild, and you're not to alter temperatures in either? Is it a case where a large-enough contiguous area of high humidity can shift small areas of hot or mild into warm?

1.5. If that is indeed the case, would hot and mild skew towards warm, or hot and warm skewing towards mild (like maritime influence?). Following that, if large masses do push the temperature, does that mean that there can be some shifting in the areas of those temperatures, even if the guide says not to touch them?

2. In my world, there happens to be a thin band of high humidity in an otherwise-'very cold' area. Following the rules, would this create an area of mild immediately surrounded by very cold, or would there be a transitional layer of cold to act as a buffer between the two values?

Any help is greatly appreciated  :Smile:

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## Pixie

Hi there. 

Nice to see people following my long abandoned ideas  :Very Happy:  ... Did you notice that at the time of this thread Azelor actually grabbed the line and took it a further step forward (much further!).

As to your questions: the answer is pretty simple. 
High humidity air is harder to take to extreme temperature. That's because water evaporation/condensation involves huge amounts of heat exchanged with the atmosphere, and also because humid air has a higher heat capacity than dry air. Meaning that the same amount of energy will take the temperature to a higher point in dry conditions, and that water vapour condensating in colder conditions will keep local air from dipping swiftly into a cold state.

This is the long explanation, now to your questions:
1 - humidity doesn't always take to Warm - it just takes areas *out of the extremes of the range*. So, no, by that reasoning, a large hot area with high humidity will still be hot.
1 (2nd part) - the two factors are done separately, apply one, then apply the other one, it may just happen that you skew the very hot/ hot boundary in one direction, then you skew it back to its original place.

2 - very cold steps up to cold, and where it was cold before, steps up to mild (...if I remember correctly) - where does Warm come from? Always have the intermediate levels. Take care not to change one level into another level you haven't adjusted before, or you will end up doubling what should be a one-step change.

Hope it helps.
I'm glad you're using this guide. Why not starting your own W.I.P. (work in progress) thread in this forum and share what you have? And also, what I would recommend nowadays is to use my guide, then use Azelor's, independently, and then use the two as a guide for your own take on your planet (kind of take an average between them).

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## PaGaN

Hi Pixie.

Just wanted to stop by and say "Hi" and say thanks this now venerable awesome thread. I was a lurker for a while but finally jumped in for expert advice for the world i'm working on.

Started my WIP post up in World Mapping (pending approval before it's viewable).

When i get to the climate mapping i will be starting off with this here guide that you gave to us all and it would be great if i could call on you for an objective opinion and some input if you wouldn't mind... :Wink: 

Anywho, that's it for now.

PaGaN

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## Pixie

Thanks for the compliment, PaGaN. 

Azelor followed up on this thread and created a better/different tutorial. You might want to dig it as well. In fact, Azelor and I take turns (not on purpose) in being active here at the guild and he's much more available than I am nowadays. He really is the go-to guy for climate  :Very Happy:

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## PaGaN

Hey Pixie!

Compliment is well deserved.

If i'm being honest I found it easer to follow your guide along to the temp and precipitation stages. The way you broke down the various zones and categories using the screen blend mode seemed a little clearer. I read Azelor's guide IN ITS ENTIRETY! LOL (that was a mission  :Wink: ). I'll stop by, subscribe to that thread and give Azelor a wave.

Regardless, your feedback and opinion will always be welcomed.

Thanks for getting back to me.

PaGaN

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## arch-fiend

sorry for necroing this thread as many have done before me. im aware that azelor has made an updated guide based around this one a long time ago, but i used this guide like 2 years ago and i used it again recently, and i just discovered and wanted to point out that your rules for maritime subpolar and taiga conflict




> 14. MARITIME SUBPOLAR (Cfc)
> - one season is Warm/Mild and one is Very Cold/Extremely cold
> - both seasons are Moderate or above





> 17. TAIGA (Dfc/Dsc/Dwc)
> - warmer season is Warm/Mild and colder season is Very Cold/Extremely Cold
> - not qualified as Cold Steppe or any other D-type climate


its very unlikely for the cold season to have a warm/mild climate which overlaps with a warm season very cold/extremely cold climate thus the taiga is going to dominate practicaly all zones that maritime subpolar is likely to find itself in. so im wondering which should be dominant in your guide?

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## Azélor

The cc (not just cfc) definition is definitely wrong.

The average temperatures can't go below zero. 
I think the coldest they can go is mild, but Pixie never gave the temperature equivalent for these categories. 

You are right, the taiga covers most of the area. Cc climates are rare.

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## arch-fiend

i see, this might also explain why i have some parts of my map which are very wet year round and mild or warm/mild all year round which have no input at all. that's not likely to happen on a map on earth but i have some large islands which have northern coasts under the polar front all year while also being warmed by a warm ocean current which i dont think happens anywhere on earth

theres a few other gaps as well. in general i think pixie did a great job, theres a reason ive used this guide twice in 2 years, but needs some refining, and as i understand it i think azelor's guide might do that.

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## CTA

Hey! First of all, this is super cool. Second, I was wondering how you made the height map you show in your second post. I've been poking around but haven't found any good resources, so any advice you could give would be greatly appreciated! (working on a tectonics map rn) Thank you so much!

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## Azélor

> Hey! First of all, this is super cool. Second, I was wondering how you made the height map you show in your second post. I've been poking around but haven't found any good resources, so any advice you could give would be greatly appreciated! (working on a tectonics map rn) Thank you so much!


It's mostly done by hand with trial and error but more specifically:  https://www.cartographersguild.com/s...ad.php?t=25903

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## CTA

That is an awe-inspiring amount of work. I mainly want a map to serve as guidance in climate construction; do you think a substantially lower-resolution topographic map (like this) would work for that? If so, what actually determines how high things are? From the maps I've seen so far, it looks like "things are high near plate collision zones and get lower as you move further away from them" is a standard rule, but that's probably a gross oversimplification.

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## CTA

Whoa, impressive. I'm mainly interested in topography for climate purposes (at least for now), so I figure I don't need to be quite that detailed. Broadly speaking, how do you figure out which regions should be at which elevations? From what I've seen it seems like "subduction zones and continental collisions are high, and things get lower as you move further away" is a decent rule, but I'm sure that's a gross oversimplification.

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## Rob Andrews

> Hi folks.
> 
> Been working every now and then at the detailed heightmap of this world but I also spent some time in related projects (some hobby free time... which isn't as much these days as I would like it to be). One of them is this one.
> 
> With a fairly detailed map of the one continent, I could work a nice climate map as well. This I did, and then redid, and then again. And every time I added a little more depth and a better understanding of climate. I also used Geoff's Climate Cookbook everytime. In the meanwhile other members were also working on climates and I thought there could be more in terms of guidance for that. Hence, I thought I could, perhaps, redo my climate map in nice smallish steps and make it public.
> 
> Should the outcome and the process be of any "learning use", I will turn this into a pretty pdf for tutorial purposes..
> 
> So this is how I am doing it:


Pixie - discovered this a new user seven years after the original post and wanted to commend you for a brilliant piece of work.  I applied your method to my own world and amd really happy with the results.  I haven't finished yet but the process was brilliant!  I found this link from Artifexian's world building tutotrials on YouTube and found that your system produces and extremely realistic climate system.  Maybe more overkill than most would bother with, but that's the way I like to do my world building!  Thanks for the work and the sharing.  When I am done I will share the physical feature map and the final climate map.

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## Rob Andrews

This was so impressive and useful.  I followed the process and in the end had to develop six new climates!  Currents and winds ended up creating some interesting conditions and my world has some plate tectonics that generated some pretty epic mountains, so elevation plays a pretty major role.  I am showing a base physical map which is essentially shaded elevation, then a climate map created using this process, and then a biome map.  I will also be creating a terrain map to show ground cover, which will be an amalgam of all of these.

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## WoodytheClimateGuy

One Question though: In what manner would the ITCZ would move? Would it move upwards based on elevation or something?

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