The Problems with Superpowers

Thank you for the detailed explanation.

Wind chill comes from two parts: wind helping evaporation happen faster and the moving air preventing the build up of any heat in the air around your body (i.e. loss of an insulating layer of air, and no air partially warming up). If you look at a wind chill table of values, typically by the time you reach 50 mph, increasing the wind speed any more won't make much of a difference. Once all of the air in contact with your body is at ambient temperature, moving more air past it won't cool it any faster.

So the faster you go, the less an effect of cooling, while the effect of heating grows, even without breaking the sound barrier. Someone comments here it can be noticeable at ~63% the speed of sound. It looks like they are using the stagnation temperature, which assumes a parcel of air going from zero to full speed of the object it is hitting, then it would have to undergo some squeezing and heating. Most of the air doesn't do that around an object, as most of the air gets pushed aside instead of piling up in front of an object. Except, when going faster than sound it then has trouble moving out of the way fast enough, so then the heating really takes off there. So that estimate is a crude upper bound that becomes less crude above the speed of sound. At around the speed of sound, 17 C air would could reach up to 75 C piling up in front of a person. I've seen references in the past (maybe misremembering, can't find them at the moment) that humans can survive surprisingly high air temperatures for a couple minutes at a time, as in possibly approaching 100 C, but it probably doesn't take moving air into account.

The numbers are a bit different for airplanes, because they fly at altitudes where it is much colder than at the surface and they are more aerodynamic, but the heating on supersonic planes like the Concorde and SR71 is considerable. The Concorde would expand enough from thermal expansion to create a gap behind one of the control consoles in the cockpit, big enough that pilots stuck their hat in it when the Concorde retired. The SR-71 leaks fuel on the ground, because there are gaps in panels that close up once it gets to cruising speed.

I didn't know that. Thank you for explaining.

Would it be colder prior to breaking that shock wave?