Humidity

Each space has between 0 and 4 Humidity. Whether a space has at least 1 Humidity affects the changes in weather on that space during the Weather phase.

Spaces with at least 1 Humidity and without Snow support the growth of Crops from Soil and of Forests from Grass.

Grass tiles in spaces without humidity become Dirt. Crops tiles in spaces without humidity become Soil. Dirt and Soil tiles in spaces without humidity become Desert if at least 20% of the map is covered with Chaos. Desert tiles without humidity suffer from Bonedrought if at least 40% of the map is covered with Chaos.

For every 20% of the map that is covered with Chaos, a random selection of 3% of the map suffers from Aridification, prefering Grass, Dirt, Desert, Rubble, Soil and Crops and avoiding other tiles if possible. This causes each of those spaces and all surrounding spaces to lose humidity.

In Autumn, Industry tiles cause surrounding spaces to lose humidity.