A typical tropical rainforest receives about 250 centimeters of rain each year. That is roughly 2.5 meters, or 98 inches, of precipitation—far more than most temperate environments receive.
Rainfall is not evenly distributed among all rainforests. The usual range is approximately 175 to 300 centimeters annually, while exceptionally wet locations can receive much more. A true tropical rainforest generally has no pronounced dry season, and each month commonly receives substantial precipitation.
Warm temperatures drive rapid evaporation, and plants release water vapor through transpiration. Moist air rises, cools, and produces frequent convectional rain, helping create the humid conditions that sustain dense forests. Despite the abundance of water, many rainforest soils are nutrient-poor because heavy rain leaches minerals away.
The 250-centimeter figure is an average benchmark, not a universal measurement. The Amazon, Congo Basin, and Southeast Asian rainforests all contain wetter and drier regions, and seasonal tropical forests may receive less rain.