Who said anything about attaining high degrees of precision and accuracy? Obviously elevation comes into play too. We’re just taking about a scale that is based on the properties of an extremely abundant natural element.
Well yes, but by that argument we should be measuring all temperatures in milli-Kelvin.
Anyway, the real reason Celsius is superior to Fahrenheit is that it’s a world standard. Other concerns are minor in comparison. It still annoys me to no end that I can’t use a cookbook from home (Japan) or recipes from European web sites without doing unit conversions.
This is simply not true. If it were, NIST (and every other PSL) would not have mandated the TP of water to be a defining point of the ITS and TTS.
In fact, of all the fixed points defined by the ITS, the TP of water has the best reproducibility (which is one of the reasons why it was chosen to be one of only two defining fixed points that link the TTS with the ITS). Of course, in order to make a practical TP of water cell, the manufacturer has to pay careful attention to the isotopic composition and the presence of impurities. But the net result is that a properly-made TP of water cell outperforms every other fixed-point cell.
Right. But Fahrenheit could have been a world standard, too.
The bottom line is that, with the exception of Fahrenheit’s superior “whole number resolution” (or whatever you want to call it), neither scale has an advantage over the other. And I readily admit the “resolution” argument in favor of the Fahrenheit scale is dubious at best.
Derleth beat me to the punch line on this one. It’s all what you’re used to. My brother in Arizona is outside in 110 degree (F) heat all the time. Here in Montana, I often don’t put on a coat if it’s zero degrees F and I’m just going outside for five minutes or so just to feed the goats. I’ve been out chasing cattle on horseback at 40 below zero (C or F, take your pick). I spent three hours clearing snow on a tractor with no cab at 20 below F. Somehow, I didn’t die. 
In fact, my son was out on the trampoline at 15 degrees F wearing just socks, long pants, and a t-shirt the other day.
Are they really as accurate as commonly believed? See Evaluations of Water Triple Point Cells: A Summary Report of Recent International Intercomparisons.
Can we do better? Water was an obvious reference material when these scales were developed. Things became more complicated when isotopes were discovered. How difficult would it be to separate the isotopes and produce nearly pure “light water”?
How much does a cubic yard of water weigh?
Are you seconding-guessing the temperature metrologists at NIST? Those guys aren’t idiots; they’ve spent decades trying improve temperature accuracy 1 μK at a time. If there was a better way to do it, do you not think they’d be on top of it?
Now having said that, TP water cells are not perfect by any means; they do exhibit some offset error. But they’re better than anything else out there. If you come up with a more accurate & reproducible fixed-point cell, by all means give the guys at NIST a call ASAP.
FYI, here in our precision thermometry lab, we maintain three TP water cells round-the-clock. Our SPRTs can detect a very slight difference between the cells, but it’s not statistically significant for the calibrations we’re doing.
This is just not true. 0 degrees F is not exactly balmy, but I probably wouldn’t wear a hat.
- 10 F is starting to get sort of nippy - I would put on a hat, and my medium thickness winter coat
-20 F is pretty cold. I’d wear a hat/scarf and my heavy mittens
-40 is cold. I’d wear my fattest coat, hat, scarf, fat mittens and pants. However, I would still wait for the bus for about 20 minutes and not notice it too much, as long as there wasn’t a gale force wind.
If you add in a wind, then I would be crabby. But I’d still wait for the bus. And wear my Sorels.
Actually, I just checked - 0 F is about -17 C - I would probably wear a head band around my ears.
Never mind definitions of temperature, we need definitions of coat. I strongly suspect that my big thick winter coat, which has never seen below -15c, would seem pathetic alongside your ‘medium thickness’ one.
It really doesn’t matter what the original definition of a metre was, in fact it is currently defined in terms of the wavelength of light in a vacuum. The point is that the metric scale was methodically set out to have specific relationships between the different units of measure; these relationships are not coincidental and are simply not present in the Imperial/English system, unless you change the size of some of the units, then (as I said), you’re merely reinventing something like the metric system.
Indeed. In my fattest coat, I’m actually the shape and dimension of a polar bear, so there you go. 
Did nobody else notice this one? To me, 15 = Better wear shorts today.
And yes, I use the Celsius scale, even here in Montana. Call me a rebel.
Incidentally, there is one significant change in weather effects at around 0 Farenheit. Right around there is the temperature where an appropriately-dressed human can lie down in the snow without it melting (of course, this varies a bit from person to person, but it’s in that vicinity). Which actually makes winter camping rather more pleasant just below 0 F than just above it. And yes, despite what some Southerners may think, it’s perfectly possible to dress appropriately for temperatures below 0 F (though when it gets down to -40, I’ll just stay inside and wait for alice_in_wonderland).
Boy am I glad I don’t live in Canada.
Around these parts, 0 F is about where “really cold” becomes “freakishly cold.” Only in an unusually harsh winter do we need to dust off the minus sign. On the other end, 100 F makes for an unusually hot summer around here. Fahrenheit just makes for a convenient temperature scale for temperate climates.
Well, I’m never going to drink a liter of water at a time, so I want pints. Actually, scratch that, I always thought pints were kinda useless, so I just use cups. 
I mean, honestly, Half-Pints? :dubious: They can’t sell the little cartons of milk by the cup? IT’S THE SAME THING :smack:
Out of curiosity, how much heating oil do you buy at a time? (I don’t have to buy the stuff in Texas), and how often do you find yourself NEEDING precision when buying gasoline? :dubious: I just stick the nozzle in the gas tank and squeeze until it’s full. Sometimes I’ll even look at the pump to see how much gas I’ve gotten so far.
WHO CARES? 
Heh, I own two jackets. One for when I’m wearing a light colored shirt, the other for when I’m wearing a dark colored shirt. They’re both about thick enough for a really cold day in Texas if I walk quickly enough to make my blood flow (so, say, low 70’s? :D)
I wonder if we could pesuade some international scientific body to develop a standard unit of coat? Like, a windbreaker would be 2 degrees Jacket (J), a leather jacket would be around 4-6 J, a parka would be 10 or 15 J, and a Tom Tom sliced open is 100 J. 
And as a side note, I think Canadian Dopers should be barred from using their own temperature comfort zones as a barometer for which temperature system is better. Just to be safe, let’s exclude any Ecuadorian Dopers from doing this as well.
Here’s a simply way for Americans to figure out Celsius for weather purposes.
We have to remember just 3 pairs of numbers. (I’m assuming that most already know 0 C. = 32 F.)
10 C. = 50 F.
20 C. = 68 F.
30 C. = 86 F. (Just the reverse of 20 C. )
Every additional 10 C. equals 18 more F. and 5 C. equals 9 more F. but these 3 pairs will help you through most weather reports.
This is a joke isn’t it? Humans evolved in an environment where 100F was a normal summer temperature. It’s about as dangerous to us as 0F is to a polar bear. There’s nothing even remotely dangerous about 100F, even working outside in full sun. Yes it’s uncomfortable, but unless you are stupid enough to allow yourself to dehydrate it’s not dangerously hot. And of course if you are stupid enough to dehydrate 40F is dangerously hot.
And how is this relevant to this thread?
In every thread about Celsius vs. Fahrenheit, someone says “system A is intuitive - X degrees is hot, Y degrees is cold, that’s it.” Someone always counters with “You call X hot / Y cold? Wimps!” I still don’t understand why that’s a valid or useful counter-argument.
ANd IIRC it isn’t metric. Kilojoules are its metric equivalent. 4.19kJ=1 cal. Although I hope I am not getting SI and metric confused.