Weather Generator, Part 3: Climate Templates

Illustration from "Weather in the World of Greyhawk" from The Dragon #68

Previous posts:

Part 1, here.

Part 2, here.

Download the Weather Generator, here.

Today, we'll look at the second tab or sheet from the left - Climate Templates.

For each climate zone you create, you'll start with one of the twelve pre-set climate templates contained in this tab. 

Three important things to note:

1. While there are only twelve templates (I haven't yet built in any slots for additional ones), each can be tweaked, modified or completely redesigned from scratch by the user.

2. The templates are templates, nothing more. You can still individually adjust most things within each particular climate zone. For example, you can use the same Desert template for two different climate zones in different latitudes. In one, you can lower the average temperature by 20 degrees. In another, you can increase the precipitation chances from 5% to 15%. And so on.

3. I tried to set up the templates to be "realistic" (working off initial numbers presented in The Dragon 137), so you don't need to change anything. Of course, your world may be quite different from Earth, or you may think I'm just wrong about the length of desert seasons (which is quite possible) or whatever. In that case, change it! 

Each template is actually quite simple, containing three sets of information:

1. The timing and duration of seasons. Does "Summer" in north temperate coastal areas last from June through September or merely July to August? And so on.

2. Each month's precipitation chances. This is roughly the chance per day that there will be a precipitation event. Again, you can change the numbers here, or you can wait to further tweak them in a general way for a particular climate zone. For example, if Tropics I (Coastal with Rainy Season) has 10% precipitation for seven months and 85% precipitation for the remaining five months, in your own "Super Monsoon" zone, you can change it to 20%/95%.

3. For each season, what is the range of temperatures? You read the numbers this way: If the range for Fall/Spring of Tropics I in the 96-00 category is 110 to 120, that means there's a 5% chance per day that the temperature will be within the upper range of 110 to 120 degrees Fahrenheit.

Here is an example of one climate template:

And here is the full list:

1. Tropics I (Coastal with Rainy Season)
2. Tropics II (Inland Swamp or Jungle)
3. Tropics III (Savanna, etc.)
4. Tropics IV (Desert)
5. South Temperate I (Coastal Warm and Rainy)
6. South Temperate II (Coastal Hot)
7. South Temperate III (Southern Steppes)
8. South Temperate IV (Forest, Hills or Mountains)
9. North Temperate I (Coastal)
10. North Temperate II (Inland)
11. Polar I (Coastal)
12. Polar II (Inland)

There are four Latitude zones - 0-25º, 25-50º, 50-70º and 70-90º. Each has at the least, a coastal climate zone and an inland climate zone. But the two southern most Latitude zones each have two additional zones.

Seasons vary less the closer one gets to the Equator. On the other hand, there are more geographic climate options.

The original templates (and my tweaks) are probably more European than American. I've lived in Boston, Chicago and London. Boston and Chicago are actually 10 degrees south of London. But Boston and Chicago get colder. Indeed, they also get warmer.

So, if you want "American" values as opposed to "European," make the winters colder and the summers hotter. In this regard, Asia (or at least the Asian Eastern coast), may be even more American than America. 

Cheers, weather nerds!

Tomorrow, the Climate Zones themselves.