# windchill below 0 K?
**URL:** https://boards.straightdope.com/t/windchill-below-0-k/225796
**Category:** Factual Questions
**Created:** [January 23, 2004, 6:33pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796 "2004-01-23T18:33:29Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@quelquechose](https://boards.straightdope.com/u/quelquechose)
#### Post date: [January 23, 2004, 6:33pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/1 "2004-01-23T18:33:29Z")
Is there any reason why windchill could not go below absolute zero? It seems like it should be able to, but it still seems strange. Also, what temperature wind relationship (equation or inequality) will give 0 K or below windchill, if it is possible?
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### Author:  [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)
#### Post date: [January 23, 2004, 6:37pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/2 "2004-01-23T18:37:09Z")
Would the air itself be frozen out by a zero-K temperature? I think that’ would pass gases into liquid into solid pretty quickly.
Therefore, no wind.
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### Author:  [@detop](https://boards.straightdope.com/u/detop)
#### Post date: [January 23, 2004, 6:37pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/3 "2004-01-23T18:37:30Z")
Seems to me it would be impossible, because at this temperature, even the **air** would be frozen.
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### Author:  [@Steve\_Wright](https://boards.straightdope.com/u/Steve_Wright)
#### Post date: [January 23, 2004, 6:40pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/4 "2004-01-23T18:40:02Z")
I am not a physicist, but …
Doesn’t absolute zero (0 Kelvin) mean the absence of molecular motion? If there’s wind about, you have molecules moving, ergo, a temperature above absolute zero … ergo, the situation you’re describing can’t happen.
Quick, somebody who knows what they’re talking about, come and explain to me!
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### Author:  [@Colibri](https://boards.straightdope.com/u/Colibri)
#### Post date: [January 23, 2004, 6:41pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/5 "2004-01-23T18:41:25Z")
> [@quelquechose](#):
>
> Is there any reason why windchill could not go below absolute zero? It seems like it should be able to, but it still seems strange. Also, what temperature wind relationship (equation or inequality) will give 0 K or below windchill, if it is possible?
Since all substances (except for helium) are solid anywhere near absolute zero, how would you get wind?
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### Author:  [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)
#### Post date: [January 23, 2004, 6:47pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/6 "2004-01-23T18:47:29Z")
> [@Jonathan Chance](#):
>
> Would the air itself be frozen out by a zero-K temperature? I think that’ would pass gases into liquid into solid pretty quickly.
>
> Therefore, no wind.
I could be wrong (and I usually am) but windchill has to do with a human’s perception of temperature. When the wind is blowing hard, all of our radiated heat is imediately blown away and we feel colder than if there was no wind. Windchill is more qualitative than quantitative. It’s about how cold we feel, not how cold the instruments say it is.
So, since our nerve cells would not function at 0K anyway, it wouldn’t feel like anything. There is no windchill factor when the wind no longer changes our perception of ambient temperature.
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### Author:  [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [January 23, 2004, 6:52pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/7 "2004-01-23T18:52:51Z")
Wind chill is supposed to indicate that you’re in a forced convection environment where the heat transfer from a warm body is equivalent to the natural convection and conduction at a much colder temperature. That is, it’s a measure of heat transfer rates, not actual temperatures. So, if you put a very warm body in a very fast flowing cold airstream, you could set it up where it has a heat transfer rate which is equivalent to what the warm body would have in a still fluid at absolute zero. It’s irrelevant that you can’t actually reach absolute zero or what would happen to substances if you did because wind chill is only a measure of heat transfer rates, not actual temperatures.
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### Author:  [@Duke](https://boards.straightdope.com/u/Duke)
#### Post date: [January 23, 2004, 7:11pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/8 "2004-01-23T19:11:11Z")
In the strictest sense, it should be possible to calculate a “wind chill” of less than 0K. [The formula that the US Weather Service uses to calculate wind chill](http://www.usatoday.com/weather/resources/basics/windchill/wind-chill-formulas.htm) is
> [@](#):
>
> Wind chill temperature = 35.74 + 0.6215T - 35.75V (\*\*0.16) + 0.4275TV(\*\*0.16)
where T=temperature in degrees Fahrenheit and V=velocity of wind in miles per hour, and \*\* stands for exponent. I don’t have a scientific calcluator handy, but I am sure there is a point where sufficiently high wind speeds, even at temperatures well above 0K, would result in a less-than-0K calculated wind chill.
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### Author:  [@spingears](https://boards.straightdope.com/u/spingears)
#### Post date: [January 23, 2004, 7:13pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/9 "2004-01-23T19:13:15Z")
Liquid Air boils at approx -195 C.
Since the air is liquid at that temperature, AKA the critical point, there can be no wind, and hence no wind …
Absolute Zero approx. -273 K has been approached in the lab but is yet to be realized.
Wind chill is an arbitrary empirical formulation of the effect of wind speed, humidity, and ambient temperature on human flesh. I has been changed at times as more is learned about the specifics.
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### Author:  [@Colophon](https://boards.straightdope.com/u/Colophon)
#### Post date: [January 23, 2004, 7:17pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/10 "2004-01-23T19:17:29Z")
[Pulp Fiction]
**Is the windchill 0K?**
Naw man, it’s pretty f\*\*\*\*\*\* far from 0K…
[/Pulp Fiction]
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### Author:  [@cmurdough](https://boards.straightdope.com/u/cmurdough)
#### Post date: [January 23, 2004, 7:48pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/11 "2004-01-23T19:48:42Z")
Absolute Zero approx. -273 K has been approached in the lab but is yet to be realized.
-273 C
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### Author:  [@cmurdough](https://boards.straightdope.com/u/cmurdough)
#### Post date: [January 23, 2004, 7:52pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/12 "2004-01-23T19:52:56Z")
By the way, how do you put people’s statements in those boxes so people know you’re quoting someone and then commenting on what they wrote?
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### Author:  [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [January 23, 2004, 8:04pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/13 "2004-01-23T20:04:19Z")
> [@Duke](#):
>
> Wind chill temperature = 35.74 + 0.6215T - 35.75V (\*\*0.16) + 0.4275TV(\*\*0.16)
So, if I scribbled on my envelope accurately…
If you take a reasonable temperature, say -129 degF (the record at Vostok), you’d need a something like a 12,000 mph wind to get a wind chill of absolute zero. If you take a reasonable wind, say 175 mph (cat5 hurricane), you’d need a temperature of -260 degF.
So, it’s not going to happen on Earth until we have some radical climate shifts, but the point is that reality of absolute zero has very little to do with a wind chill of absolute zero.
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### Author:  [@Tusculan](https://boards.straightdope.com/u/Tusculan)
#### Post date: [January 23, 2004, 8:10pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/14 "2004-01-23T20:10:34Z")
> [@cmurdough](#):
>
> By the way, how do you put people’s statements in those boxes so people know you’re quoting someone and then commenting on what they wrote?
You can only do that when you have over 100 posts, and have paid the customary chocolate tribute to **Lynn**.
: wswsswswswswswsh :
Oh, apparently these days _everyone_ can do this.
All right, here’s what you do. Instead of using the big inviting ‘Reply’ button at the bottom of the thread, you use the small ‘reply’ button at the right bottom of the post you want to quote. This will provide you with a reply box with the quote pre-entered. Look at the coding, and remember it for if you want to do this by hand. Capisce?
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### Author:  [@spingears](https://boards.straightdope.com/u/spingears)
#### Post date: [January 23, 2004, 8:17pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/15 "2004-01-23T20:17:04Z")
> [@Duke](#):
>
> In the strictest sense, it should be possible to calculate a “wind chill” of less than 0K. [The formula that the US Weather Service uses to calculate wind chill](http://www.usatoday.com/weather/resources/basics/windchill/wind-chill-formulas.htm) is where T=temperature in degrees Fahrenheit and V=velocity of wind in miles per hour, and \*\* stands for exponent. I don’t have a scientific calcluator handy, but I am sure there is a point where sufficiently high wind speeds, even at temperatures well above 0K, would result in a less-than-0K calculated wind chill.
Interesting but of doubtful value!
The result of such calculations, based on bad assumptions and following a mechanical procedure are 'absolute’ly devoid meaning. [An exercise in mental Onanism.]
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### Author:  [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [January 23, 2004, 9:24pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/16 "2004-01-23T21:24:30Z")
> [@spingears](#):
>
> Interesting but of doubtful value!
I’ll grant that the numbers I calculated above are of little practical value in themselves, but I think the exercise is very instructive. The point is that you can easily calculate a wind chill factor colder than absolute zero, and this helps understand what exactly wind chill is. As evidenced by all the posts in this thread regarding the physical properties of material at absolute zero, that understanding is needed.
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### Author:  [@Colibri](https://boards.straightdope.com/u/Colibri)
#### Post date: [January 23, 2004, 9:49pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/17 "2004-01-23T21:49:32Z")
> [@micco](#):
>
> I’ll grant that the numbers I calculated above are of little practical value in themselves, but I think the exercise is very instructive. The point is that you can easily calculate a wind chill factor colder than absolute zero, and this helps understand what exactly wind chill is. As evidenced by all the posts in this thread regarding the physical properties of material at absolute zero, that understanding is needed.
It’s rather obscure whether the OP was asking whether a wind chill factor could be _calculated_ that went below absolute zero, or whether a wind-chill effect could actually _cool_ something below absolute zero. Given the cluelessness of some of the questions I’ve seen posted here, the second possibility cannot be discounted. Therefore an explanation of the properties of matter near absolute zero is was entirely warranted.
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### Author:  [@quelquechose](https://boards.straightdope.com/u/quelquechose)
#### Post date: [January 23, 2004, 10:09pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/18 "2004-01-23T22:09:30Z")
> [@](#):
>
> It’s rather obscure whether the OP was asking whether a wind chill factor could be calculated that went below absolute zero, or whether a wind-chill effect could actually cool something below absolute zero.
No, I just wanted to know if it could be calculated below absolute zero. Some other questions:
Does the wind chill change depending on the gas used? What if the atmosphere were helium?
Could a liquid produce wind chill? It seems like if I were in cold water and it were flowing past me quickly, I would feel colder than if I were sitting still.
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### Author:  [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [January 23, 2004, 10:15pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/19 "2004-01-23T22:15:21Z")
> [@Colibri](#):
>
> It’s rather obscure whether the OP was asking whether a wind chill factor could be _calculated_ that went below absolute zero, or whether a wind-chill effect could actually _cool_ something below absolute zero.
The OP seems pretty clear: can there be a windchill at or below absolute zero and, if so, what real temperature/wind conditions would it take. Clearly you can have a wind chill below absolute zero and the physical properties of air at a real temperature of absolute zero are irrelevant. But that’s my interpretation and I’m clearly not the judge of what’s relevant.
If there is confusion about whether wind chill could cool a body down to absolute zero, it should be noted that a wind chill cannot cool something below the real ambient temperature. For example, if it’s 30 degF and the wind chill is 10 degF, a warm body will only cool to 30 degF. Once it’s at the ambient temperature, wind chill is no longer an issue. Wind chill isn’t a real temperature; it’s simply a way of relating to increased heat transfer rates caused by forced convection.
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### Author:  [@micco](https://boards.straightdope.com/u/micco)
#### Post date: [January 23, 2004, 10:31pm UTC](https://boards.straightdope.com/t/windchill-below-0-k/225796/20 "2004-01-23T22:31:12Z")
> [@quelquechose](#):
>
> Does the wind chill change depending on the gas used? What if the atmosphere were helium?
Yes, the type of gas does affect the heat transfer rates which wind chill is supposed to indicate, so a helium atmosphere would lead to a different temperature/velocity relationship. I don’t have my old heat transfer texts handy to look up the specifics.
> [@](#):
>
> Could a liquid produce wind chill? It seems like if I were in cold water and it were flowing past me quickly, I would feel colder than if I were sitting still.
Yes. This is stretching the definition of wind chill a bit, but the fundamental idea still holds. Maybe a more thorough explanation of wind chill would help explain it.
How cold you _feel_ is a measure of heat transfer, not temperature. If it’s 30 degF outside and I go out, my warm body loses heat and it feels cold. If the wind is blowing, I lose heat even faster and it feels colder than it did when there was no wind at the same temperature. Wind chill is just an attempt to quantify this “feels colder than it is” by saying that standing in this cold wind is equivalent to standing in still air that’s some colder temperature.
Water produces the same result. Heat transfer rates go up in water, which is why you can get dangerous hypothermia in a swimming pool. If you’re sitting in cold water, you could measure how fast your body was losing heat and figure out how cold the air would have to be to cause the same heat transfer rate. If the water were flowing or you’re moving around in it, you’d lose heat even faster than if you were sitting in still water, and you’d calculate an even colder equivalent air temperature.
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