Shouldn't you get hotter as wind gets stronger?

[Nano-Passion]

Physics tells us that air molecules would cause friction which in turn would make an object hotter.

So why do I freeze my off in the cold when it starts getting windy (while I'm obviously not sweating).

 

[bobze]

Physics tells us that air molecules would cause friction which in turn would make an object hotter.

So why do I freeze my off in the cold when it starts getting windy (while I'm obviously not sweating).

Because despite any heat from friction, you loose more heat via convection and evaporation Your skin is always loosing heat to evaporative cooling, even at cool temperatures. Only during extreme humidity is evaporative cooling essentially reduced to zero. That's why humid weather feels much hotter than dry weather.

 

[venton]

I guess someone needs to go out on a cold day dressed in nothing but a thin layer of cellophane and see if it feels colder when the wind starts blowing. Intuition makes me think one would feel colder, even though the cellophane would stop evaporation, but could be wrong.

 

[D H]

Because despite any heat from friction, you loose more heat via convection and evaporation Your skin is always loosing heat to evaporative cooling, even at cool temperatures. Only during extreme humidity is evaporative cooling essentially reduced to zero. That's why humid weather feels much hotter than dry weather.

Hot humid air, yes. Cold humid air, no. In my mind there isn't much worse than a cold, windy, rainy day, say 40 F / 4 C. It cuts right through everything, even if you do manage to stay dry. That is just cold and miserable, much worse than is a nice clear, calm winter day with temperatures around 20 F / -6 C. Water is an incredible conductor of heat.

 

[DaveC426913]

I guess someone needs to go out on a cold day dressed in nothing but a thin layer of cellophane and see if it feels colder when the wind starts blowing. Intuition makes me think one would feel colder, even though the cellophane would stop evaporation, but could be wrong.

You would still get conduction of heat from skin to air.

So, with cellophane, cold would still be cold, but adding wind would not make a lot of difference. I guess this is the principle by which windbreakers work. They're thin enough that they don't really prevent the loss of conduction, but they do stop the wind from removing heat by evaporation.

 

[AlephZero]

The reason is because you are not in thermal equilibrium with the air before the wind started blowing. You are generating heat internallly and losing it by mainly by convection and evaporation (sweating), plus a small amount of radiation as well. If the heat generation and loss are equal, your temperature stays constant.

You are right in the sense that there is a significant heating effect at very high wind speeds. For supersonic aircraft there can be local temperature rises of the order of 100 degrees C, and much more than that when the space shuttle re-enters the atmosphere or meteors burn up in the atmosphere. But for normal ground-level wind speeds acting on humans, the increase in convection cooling rate is much bigger than the extra heat generated, so you get colder.