Eli5: Why does the wind feel colder when you’re wet?



For example, It could be a 100° with a breeze. If you get in a pool, and then get out, the breeze makes It feel much cooler than 100°. Before getting in the pool, the breeze did nothing. Thanks for any replies.

In: Physics

Water needs energy to go from being a liquid (on your skin) to being a gas (in the air). When the wind blows, the water takes energy from the wind and energy in the form of heat from your skin and evaporates, making you feel colder because you’re losing heat.

Feeling cool or cold is the result of having heat _removed_ from you. When a breeze flows over your skin, there is a very small amount of heat transfer from your skin to the air molecules. A little, its not very efficient heat transfer. Same reason why you can stick your hand in a hot oven for quite a while before it feels uncomfortable – poor heat transfer.

When air flows over water, the water molecules near the surface that temporarily absorb more thermal energy are more excited, so they “escape” (evaporate) from the surface of the liquid, taking their thermal energy with it. The transfer of heat from your body to the water on your skin is much more efficient. When that water evaporates into the airflow, it takes that heat away, leaving the water – and your skin – that is left much cooler.

So if you’re hot and want to cool off, go soak your shirt in the pool and put it back on sopping wet.

It’s called evaporative cooling. When vaporization of a fluid takes places, the droplets that are left, on your skin, are in a state of lower kinetic energy and that equates to a relative cooling sensation.

Next time try misting water on your face when you’re super hot, fan yourself and feel the awesomeness.

Don’t forget to use sunscreen.