Evaporative cooling is a natural phenomenon that occurs when moving air passes over a wetted medium or water source, i.e. fountain, river, sea, shower, etc. The human body uses evaporative cooling through sweating to maintain a constant body temperature.

Warm dry air when passing over water liberates some of the water in the form of an evaporate. This adiabatic process converts sensible heat (that which can be measured by a thermometer) into latent heat.