# What does "ten below" mean in Fahrenheit-using countries? **URL:** \ **Category:** Factual Questions\ **Created:** [July 26, 2011, 1:08pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377 "2011-07-26T13:08:19Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 26, 2011, 6:40pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/61 "2011-07-26T18:40:22Z")
> [@Lemur866](#): > > No, 100F was supposed to be body temperature, and 0F was the coldest salt and ice brine that Fahrenheit could make. Fahrenheit was looking to make 0 to 100 correspond to the coldest and hottest temperatures one could expect in Europe, but you can’t make a scale out of “roughly the coldest day” and “roughly the hottest day”. He needed something more constant and easily reproducible, so he chose exactly what you posted. He fiddled around a bit before finally settling on those though. The brine mixture that you mentioned proved to automatically stabilize itself so it made a good temperature reference. On the hot side he played around with things like human body temperature and also with Ole Romer’s original scale, multiplied by four to get the numbers into roughly the range he wanted. After some fiddling with one of his revised scales, he found that water boiled at something above 200 degrees. He then modified his scale so he could get water to boil at exactly 212 degrees, so that there would be exactly 180 degrees difference between the boiling and freezing points of water. Human body temperature ended up at about 98 on his revised scale. ---
**Author:** ![Mahaloth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mahaloth/32/1079_2.png) [@Mahaloth](https://boards.straightdope.com/u/Mahaloth)\ **Post date:** [July 26, 2011, 7:13pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/62 "2011-07-26T19:13:41Z")
> [@thelabdude](#): > > I can’t believe a simple question with a simple, unambiguous answer has now reached 47 posts. I know, I’m always surprised. By the way, I’m in America and say “Negative 10” or “10 below zero” if the situation arises. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [July 26, 2011, 7:49pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/63 "2011-07-26T19:49:23Z")
> [@BDoors](#): > > The record low in London is -10C. It’s never gotten colder than 14F in London? That seems amazing to me for some reason, it being as far north as it is. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [July 26, 2011, 7:51pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/64 "2011-07-26T19:51:43Z")
> [@septimus](#): > > Any other Jack London fans? I like [_To Build a Fire_](http://www.jacklondons.net/buildafire.html) which describes temperatures so low you wonder if there’s an off-by-32 error. However this is clarified in the first line of the following excerpt: > > > [@](#): > > > > Fifty degrees below zero meant eighty odd degrees of frost… This is what I came to post about. [Degrees of frost](http://en.wikipedia.org/wiki/Degree_of_frost) was formerly a common way of quantifying temperatures below freezing. I’ve seen it a lot in books about Arctic and Antarctic expeditions. Three degrees of frost means 29 F. Likewise 3 degrees of fever refers to a body temperature 3 degrees above normal body temperature, or about 101.6 F. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 26, 2011, 8:03pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/65 "2011-07-26T20:03:08Z")
> [@jtgain](#): > > It’s never gotten colder than 14F in London? That seems amazing to me for some reason, it being as far north as it is. The wind patterns and ocean currents (specifically the North Atlantic Current) tend to make the weather in England fairly mild. The summers don’t get too hot and the winters don’t get too cold. Those same wind and ocean currents also make England windy and give it some fairly unpredictable weather. You can have hot T-shirt and shorts weather one week and be in light jackets the next (at least that’s the way it has been every time I’ve gone over there to visit relatives). ---
**Author:** ![BDoors](https://avatars.discourse-cdn.com/v4/letter/b/e95f7d/32.png) [@BDoors](https://boards.straightdope.com/u/BDoors)\ **Post date:** [July 26, 2011, 8:09pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/66 "2011-07-26T20:09:01Z")
> [@jtgain](#): > > It’s never gotten colder than 14F in London? That seems amazing to me for some reason, it being as far north as it is. I got that from the BBC weather pages: [London - BBC Weather](http://news.bbc.co.uk/weather/forecast/8#) , click More then Average Conditions. ---
**Author:** ![MarcusF](https://avatars.discourse-cdn.com/v4/letter/m/67e7ee/32.png) [@MarcusF](https://boards.straightdope.com/u/MarcusF)\ **Post date:** [July 26, 2011, 9:00pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/67 "2011-07-26T21:00:28Z")
London is a special case - massive city with its own micro-climate. Out in the English countryside the coldest temperature measured was -26C - say “15 below”. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [July 26, 2011, 10:22pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/68 "2011-07-26T22:22:07Z")
> [@Koxinga](#): > > As opposed to the rest of the metric system (ease of convertibility into other units and all that), as far as I can see there really shouldn’t be any basis for arguing Celsius has any advantage over Fahrenheit,. In fact, the Celsius scale isn’t part of the metric system. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [July 26, 2011, 10:35pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/69 "2011-07-26T22:35:39Z")
> [@jtgain](#): > > It’s never gotten colder than 14F in London? That seems amazing to me for some reason, it being as far north as it is. At the same latitude, temperatures in Western Europe and in America are widly different. This is due in part to the Gulf Stream, bringing hot water to the European coasts, and in part to the cold wind regime in eastern North-America. Usual winter temperatures in, say Canada are absurdly low by comparison with Europe at the same latitude (so much so that I’m even unable to imagine how cold say, -30 °C, could be like. I guess you just drop dead if you leave your house or something). And having a very oceanic climate, the UK is even more peculiar, with usually a very short range of temperatures by comparison with the continent. It’s essentially never really cold and never really hot there. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [July 26, 2011, 10:38pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/70 "2011-07-26T22:38:45Z")
I don’t want to play a game of “I’m tougher than you” because I don’t really like cold weather that much. I lived in Ann Arbor for 8 years and that was enough cold weather for a lifetime for me. And A[sup]2[/sup] isn’t even that cold. But you recalibrate depending on what you’ve experienced. In the DC area I \*hate \*it when it’s 45[sup]o[/sup]F and these wussies tell me it’s cold. > [@Motorgirl](#): > > …when it is significantly below 32 it is “wicked cold” and when it is below 0 it is “f-ing cold.” HTH > [@Merneith](#): > > Freezing > Cold > Really Cold > Really Fucking Cold > Zero > Below Zero > Ridiculously Cold > Witches’ Tits. My F scale would be 45: Put the top up, it’s getting chilly 32: Put a coat on, it’s getting cold, and watch for black ice 20: brush the frost off your moustache, it’s pretty cold 0: Now \*that’s \*cold. Put on gloves and a hat if you have to go out even for a few minutes. -10: \*Now \*it’s fucking cold. Let the dog in. I have never been in weather colder than -10 but I am going to call that “take the next plane to Hawaii.” ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [July 26, 2011, 11:08pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/71 "2011-07-26T23:08:19Z")
> [@TriPolar](#): > > The Fahrenheit scale is much maligned, but it does suit the US temperature range quite well. Temps above 100F and below 0F are very rare, so anything above or below these figures are noteworthy. Along the northern tier, temps below zero Fahrenheit are reasonably common each winter. 100+ almost never, but common enough in the desert Southwest. But by and large, zero to 100 is about the temperature range of much of the country. ---
**Author:** ![Apollyon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/apollyon/32/4238_2.png) [@Apollyon](https://boards.straightdope.com/u/Apollyon)\ **Post date:** [July 26, 2011, 11:16pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/72 "2011-07-26T23:16:03Z")
> [@clairobscur](#): > > In fact, the Celsius scale isn’t part of the metric system. Celsius has been an SI unit since 1967. [Quote=Resolution 3 of the 13th meeting of the CGPM (1967/68)] 1. a temperature interval may also be expressed in degrees Celsius; [/quote] ([cite](http://www.bipm.org/en/CGPM/db/13/3/)) ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 26, 2011, 11:37pm UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/73 "2011-07-26T23:37:42Z")
> [@BrotherCadfael](#): > > Along the northern tier, temps below zero Fahrenheit are reasonably common each winter. 100+ almost never, but common enough in the desert Southwest. But by and large, zero to 100 is about the temperature range of much of the country. It’s certainly not ideal. But it is good for weather reports. Re-reading the thread, it looks like \*\*engineer\_comp\_geek \*\*mentioned this first. But in other countries people don’t seem to have a problem reporting the weather in Celcius. The scale is in smaller units, but it’s not 1 or 2 degrees F that makes much difference anyway. Although negative numbers for common temperatures would seem strange to me. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [July 27, 2011, 12:27am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/74 "2011-07-27T00:27:26Z")
> [@TriPolar](#): > > Although negative numbers for common temperatures would seem strange to me. It’s just the convenient signal of, “Hey! It’s below freezing! Watch out for ice/more skidding cars than usual/slippery sidewalks/etc!”. I _understand_ the Fahrenheit scale; it was around in my earliest childhood in Canada. I still remember the day the first weather report was in metric. But I find the Celsius scale’s use of 0 as the signal of the great change from solid to liquid water is more logical than the Fahrenheit scale’s use of 32. ---
**Author:** ![Normal\_Phase](https://avatars.discourse-cdn.com/v4/letter/n/5f9b8f/32.png) [@Normal\_Phase](https://boards.straightdope.com/u/Normal_Phase)\ **Post date:** [July 27, 2011, 1:38am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/75 "2011-07-27T01:38:48Z")
> [@Apollyon](#): > > Celsius has been an SI unit since 1967. > > quote=Resolution 3 of the 13th meeting of the CGPM (1967/68)] > 3. a temperature interval may also be expressed in degrees Celsius; > > ([cite](http://www.bipm.org/en/CGPM/db/13/3/)) Key word: Interval. The Celsius and Fahrenheit scales are in fact equally arbitrary. However, the Kelvin scale, which is not (it bottoms out at zero = absolute zero of temperature) happens to have been based on the Celsius scale. Degrees are the exact same size, but it’s offset by 273.15 something. So while a degree difference in Celsius is exactly the same as a 1 Kelvin difference, the absolute temperatures as measured on each scale are different. “The temperature in the vessel dropped 15 degrees Celsius” is equivalent to “the temperature in the vessel dropped 15 K”, and apparently both are accepted as SI. But “the temperature was measured at 15 degrees Celsius” is not SI; the SI requires a conversion to Kelvins, or “the temperature was measured at 288 K”. And you use Kelvins for any absolute temperature needed in calculations. That makes the Celsius scale easier to use than Fahrenheit for scientific needs, because it’s one fewer conversion, yet still familiar. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [July 27, 2011, 2:07am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/76 "2011-07-27T02:07:56Z")
> [@Normal\_Phase](#): > > Key word: Interval. > > The Celsius and Fahrenheit scales are in fact equally arbitrary. However, the Kelvin scale, which is not (it bottoms out at zero = absolute zero of temperature) happens to have been based on the Celsius scale. Degrees are the exact same size, but it’s offset by 273.15 something. > > So while a degree difference in Celsius is exactly the same as a 1 Kelvin difference, the absolute temperatures as measured on each scale are different. :: nods :: Nitpick: we don’t need to capitalize “kelvin”; while the unit may be named after Lord Kelvin, only the symbol K is capitalized. Note also the difference between saying “one Celsius degree” and “one degree Celsius”: the first describes a temperature interval, which could be between many pairs of temperatures; the second describes a specific temperature. > [@Normal\_Phase](#): > > That makes the Celsius scale easier to use than Fahrenheit for scientific needs, because it’s one fewer conversion, yet still familiar. There’s also a Fahrenheit-sized equivalent to kelvins: the [Rankine scale](http://en.wikipedia.org/wiki/Rankine_scale). ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [July 27, 2011, 3:19am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/77 "2011-07-27T03:19:16Z")
> [@clairobscur](#): > > Usual winter temperatures in, say Canada are absurdly low by comparison with Europe at the same latitude (so much so that I’m even unable to imagine how cold say, -30 °C, could be like. I guess you just drop dead if you leave your house or something). In the upper Midwest, where I grew up, they would probably _cancel recess_ at that temperature — but you were still expected at school, and the adults still went to work. Society still functioned more or less as usual. Only a heavy snowfall would keep people indoors. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [July 27, 2011, 4:25am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/78 "2011-07-27T04:25:34Z")
> [@Sunspace](#): > > It’s just the convenient signal of, “Hey! It’s below freezing! Watch out for ice/more skidding cars than usual/slippery sidewalks/etc!”. > > I _understand_ the Fahrenheit scale; it was around in my earliest childhood in Canada. I still remember the day the first weather report was in metric. But I find the Celsius scale’s use of 0 as the signal of the great change from solid to liquid water is more logical than the Fahrenheit scale’s use of 32. Well there’s no arguing that Farhrenheit is logical. 32 and 212 are arbitrary, and the scale had to be adjusted to get the freezing and boiling points to be integers. I’m just used to Fahrenheit for the weather. I would find it very annoying to be a chemist and have to measure temperature in Fahrenheit. Does anyone know why the term Centigrade was abandoned in favor of Celsius? ---
**Author:** ![Jenaroph](https://avatars.discourse-cdn.com/v4/letter/j/e8c25b/32.png) [@Jenaroph](https://boards.straightdope.com/u/Jenaroph)\ **Post date:** [July 27, 2011, 4:33am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/79 "2011-07-27T04:33:33Z")
> [@CookingWithGas](#): > > My F scale would be > > 45: Put the top up, it’s getting chilly > 32: Put a coat on, it’s getting cold, and watch for black ice > 20: brush the frost off your moustache, it’s pretty cold > 0: Now \*that’s \*cold. Put on gloves and a hat if you have to go out even for a few minutes. > -10: \*Now \*it’s fucking cold. Let the dog in. > > I have never been in weather colder than -10 but I am going to call that “take the next plane to Hawaii.” I’d add in one note to your scale, 10: Boogers begin to freeze, pull your scarf up ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [July 27, 2011, 4:41am UTC](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377/80 "2011-07-27T04:41:34Z")
> [@Merneith](#): > > North American - I’ve never heard anyone, even once, say “ten below” when they were talking about 22 degrees Fahrenheit. I also don’t know anyone who bothers doing any math to figure out how far below freezing “ten below” would work out to be. Thirty-two degrees, twenty-two degrees, and ten below don’t really relate to each other. They all occupy distinct points on our mental scale which goes something like: > > Freezing > Cold > Really Cold > Really Fucking Cold > Zero > Below Zero > Ridiculously Cold > Witches’ Tits. > > In general, I would say North Americans don’t really care what the actual thermometer says - we’re more interested in the what the weatherman says about windchill factor or the humidity, probably because those are more extreme numbers. There are different North American scales too. In Wisconsin, it’s not Really Fucking cold until well Below Zero. 32 F is springtime 0 F is brisk -10 F is a might chilly. -20 F is cold -30 F is Really Fucking Cold We choose not to pay any attention to Wind Chill – that’s entirely imaginary and for pussies. [Previous page](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377.md?page=3) [Next page](https://boards.straightdope.com/t/what-does-ten-below-mean-in-fahrenheit-using-countries/590377.md?page=5)