I saw a little bit on the news on how they figure out the wind chill factor but what does “feel like” mean? Do you have to be human to feel the “feels like” temperture?
-or-
If it is 34 degrees out and the wind chill is making it “feel like” 28 degrees will water freeze??
It can; water can lose latent heat of evaporation just like a human can (well, not just like, but evaporation can cause water to freeze when the ambient temperature is above 0C.
No, actually.
Wind chill refers to the loss of body heat in a controlled environment. Your core body temperature will drop faster in a wind than in still conditions, but nothing is going to freeze unless the temperature is below freezing.
Second law of thermodynamics, IIRC.
LM, BS Meteorology
You don’t have to be human, but being warm blooded helps. Wind makes us feel colder than the reading on a thermometer because wind increases the rate at which a body loses heat. The result the formula used for the wind chill factor will produce is just an estimate of course.
I don’t believe Mangetout’s statement that evaporation will help water to freeze above 0, but it will help remove heat from water at a faster rate.
From How Stuff Works.
Wind chill in winter is perfectly anologous to humidity in summer. Wind chill makes it harder for you to retain body heat (i.e. ‘feel’ colder) and humidity makes it harder to dissipate body heat (‘feel’ hotter).
I’m not a physicist, but I’m pretty sure I’ve heard of account of ice being made by cooling by evaporation of water; the latent heat of evaporation is greater than the latent heat of fusion by a factor of about 6.8, so it sounds (to my uneducated ear, at least) possible.
WCF is supposed to quantify the effect of cold weather on exposed flesh. Right now where I live it’s -12F and the wind is blowing about 10 kts. Exposed flesh is rather scarce just now, so the advertized wind chill factor of -28 (or whatever it is) may be mostly hype.
OTOH, it is darn cold.
From here - not a particularly academic source - (I do hope we’re not going to have another thread like that one about jumping cats):