Easy Biomes for Worldbuilders

In today’s essay, we discuss a simplified and easy way to determine biomes and climate for a fictional world. We examine the major influences on rainfall and temperature, and synthesize that into a handy chart.

When designing a fictional world, the first major roadblock I hit was the determination of biomes. Deserts, jungles, forests… how do you place them in your world in a way that has an underlying logic?

Let’s assume we’re working with an Earth-like planet. Climate is incredibly complex, but for our purposes we can distill it down to simply to two variables: rainfall and temperature.

What Affects Rainfall?

1. Distance to the Equator: Rainfall often follows patterns based on distance from the equator, with tropical areas receiving the most rain.

2. Altitude: At higher altitudes, air tends to cool and can't hold as much moisture, which can lead to rain.

3. Distance to the Nearest Ocean: Regions close to oceans are more likely to receive moisture (and thus rain) carried by winds from the ocean.

4. Wind Patterns: Winds carry moisture over long distances, leading to rainfall when the air cools.

5. Rain Shadow Effect: Mountains can cause air to rise and lose its moisture on one side (windward), leading to rainfall, and descend and warm up on the other side (leeward), leading to drier conditions.