Plain English Meaning
The hidden cooling effect that happens when water turns into vapor. Evaporating water has to absorb heat from whatever is around it, so the surroundings get cooler.
Full Definition
The amount of heat energy absorbed by a liquid as it changes into a vapor, with no change in temperature during the change of state. In the atmosphere, when water evaporates from oceans, lakes, soil, or precipitation, it pulls heat energy out of the surrounding air or surface, cooling it.
Context Anchor
Seen in aviation weather discussions about moisture, temperature, evaporation, condensation, clouds, , and cooling air.