Surely the combined air molecules that are hitting your skin have the same temperature and possibly even more due to the increased kinetic energy?
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Kinetic energy of the wind is nothing compared to the thermal energy. When the air is calm, your body warms air up around itself, you are surrounded by air warmer than the room temperature. Wind blows that warm air away, so you continue losing heat at full speed.
It doesn’t.
I lived in SW Arizona for a few years and the wind felt like a hot hair dryer.
Your body doesnt “feel heat” in the sense we think it does in terms of surrounding temperature. What you actually feel is the heat loss from your body. The internal temperature of your body alighty changing due to outisde temperatures.
When the wind blows it increases the rate at which your body loses heat so it feels cooler.
The primary way we cool ourselves is via evaporation of sweat from the surface of our skin. Wind hitting sweaty skin speeds up this process and “makes the heat leave your body faster”
I could be wrong, so better wait for real OP.
But i think i still know why
Your body loses energy while sweating because it takes thermal energy to convert from a liquid (sweat) to gasous state.
Wind accelerates this procedure. Making you lose energy fast enough even if the air surrounding is “warm”.
Air moving across a surface causes evaporation of moisture which also pulls heat from the surface. So, in addition to losing the warmth held around your body when the air is still, the moving air causes your skin and clothes to cool as the warm moisture leaves.
Two combined reasons: Convection, and the subsequently increased evaporation, both increases the heat transfer from the body to the air. (Convection means air or fluid that is moving).
Human senses typically detects a change in temperature so if the air is close to body temp, it will not feel cool, unless you’re sweating…then the evaporating sweat will actually still feel cooler even at 98°C ambient…but that depends on humidity. Higher humidity means lesser evaporation.
Put a wooden spoon and a metal spoon in your fridge for some time then feel them on your skin, the metal spoon will feel much colder, despite both spoons being the same temperature (the temperature of the fridge). Now why is that?
Your body doesn’t sense temperature, but rather it senses *change* in temperature, which we like to call *heat flux*.
This heat flux depends on several factors, most notably the *temperature gradient* (the difference in temperature between the two objects). If you left the metal soon in your freezer instead of your fridge it will feel (unsurprisingly) colder.
This effect is less apparent in the wooden spoon because it’s an *insulator*. An *insulator* resists *heat flux*, reducing heat transfer and thus your sense of hot/cold. This is why we’re not constantly shivering despite the ambient temperature being lower than 37C/98.6F. Our clothes act as *insulators*, and so does the air sticking to our skin.
Wind essentially removes the *insulation* by replacing the air sticking to our skin with cold ambient air, increasing the *temperature gradient* and thus *heat flux* which our body senses as being cold.
This can also explain why wind doesn’t make you feel colder when the ambient temperature is too hot. If the wind is replacing the air on your skin with air that’s even hotter, then you won’t feel any cold. It’s also why cold water can actually feel pleasant if your hand feels “frozen” after handling something cold from the freezer for some time.
Because you’re constantly sweating and wind helps evaporation.
If your skin was 100% dry and you had wind blowing with an air temp higher than your body temp it would feel even warmer.
The human body dumps a lot of heat into the air around it. It’s basically a massive heat pump and if you stand in still air for any amount of time, it will create a noticeable increase the heat energy of the air molecules next to your skin. This reduces your body’s ability to dump heat into them. When the wind blows new air molecules next to your skin, they feel colder because your body can immediate start dumping heat into these new molecules, making your body feel colder. This is how fans make you feel colder even though from a strict thermodynamics standpoint, they are just dumping energy into the system.
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