Why do people use Celsius when the weather is cold and Fahrenheit when it's hot?
May 23, 2010 11:18 AM   Subscribe

Why do people use Celsius when the weather is cold and Fahrenheit when it's hot?

For example I often hear when it's cold people refer to it being -3 or -6 (Celsius) but they change when it's hot and refer to it being 80 or 90 degrees (Fahrenheit). I do this myself because I'm so used to it, but I was wondering where this habit started.
posted by Spamfactor to Science & Nature (39 answers total) 1 user marked this as a favorite
 
This varies by region. I live in Canada, where all radio and TV weather reporting is done in the Celsius scale, and Fahrenheit has fallen out of use pretty much entirely. For those regions that tend to use Fahrenheit when the temperature is high, it may just be that they like to use high numbers to describe a high temperature.
posted by grizzled at 11:20 AM on May 23, 2010


Where do you live? I have never heard this in the US.
posted by enn at 11:20 AM on May 23, 2010 [5 favorites]


Because no one knows what 0F means, so they use Celsius for that. Fahrenheit is used for hot temperatures because big numbers give more emphasis.
posted by blue_beetle at 11:20 AM on May 23, 2010


Where do you hear this? It's certainly not the norm in Minnesota...when we talk about it being zero degrees, we're definitely talking Fahrenheit.
posted by cabingirl at 11:21 AM on May 23, 2010


I've never heard this in the US or any other country. It's usually one or the other.
posted by dfriedman at 11:22 AM on May 23, 2010


I don't think I've ever run into this (New England & Great Lakes). However, I'd bet on two things: if you're bitching about the weather, -5° (C) sounds colder than 23° (F) and 80° (F) sounds hotter than 30° (C), and if you're talking about winter weather, 0° (C) as the freezing point is more obvious than 32° (F) as the freezing point.
posted by ubersturm at 11:25 AM on May 23, 2010 [1 favorite]


I've heard this in Australia and a bit from British people and I think it's because the hot temperatures sound more impressive in fahrenheit and vice versa. Like, 35 sounds hot, but 95 sounds even hotter!
posted by emyd at 11:28 AM on May 23, 2010


When folks want to emphasize the extremes of weather, they might shift to the scale with the bigger/smaller number, but I don't think I've really noticed this being done anywhere except in the range -10c - 10c, so I think it's more just that the freezing point is a temperature where things get the most different the fastest weather-wise, and it's convenient to use that as a basis for the scale there.
posted by aubilenon at 11:29 AM on May 23, 2010


In case this is regional, my usage observations are mostly from Boston, Minnesota, & San Francisco areas.
posted by aubilenon at 11:30 AM on May 23, 2010


Why do people use Celsius when the weather is cold and Fahrenheit when it's hot?

Because that's how temperatures would be arranged if the universe had engaged in some user testing before rolling out two conflicting systems that don't actually work very well from a user experience perspective.

It makes complete and total sense that 0 is easily understood as "very fucking cold" and 100 is read as "really really hot, but not like boiling which is a condition humans never encounter as an ambient temperature anyway."

1 - 100 is a nice range for normal human conditions, with experiences on both ends of the scale most people can put into a context. Also, it sounds more impressive to say it's zero when it's cold and 100 when it's hot. It is not impressive to say it's 20 when it's hot.

I am completely aware that from a science perspective, this makes NO SENSE. I don't care. Cold is 0 and hot is 100. Yes, my husband despairs.
posted by DarlingBri at 11:39 AM on May 23, 2010 [5 favorites]


I haven't heard of this either, unless the weatherman announces both of them, and somehow messed up the order or omitted something.

Never liked centigrade for talking about weather. "A blistering 39°" just doesn't sound as menacing as "102° in the shade".
posted by MacChimpman at 11:39 AM on May 23, 2010 [1 favorite]


It makes complete and total sense that 0 is easily understood as "very fucking cold" and 100 is read as "really really hot, but not like boiling which is a condition humans never encounter as an ambient temperature anyway."

I suspect this depends on the local climate. In most places I've lived, neither 0° F nor 100° F would be terribly uncommon temperatures, and 0° C wouldn't be considered very cold at all.
posted by enn at 11:43 AM on May 23, 2010


Why do people use Celsius when the weather is cold and Fahrenheit when it's hot?

They do not. At least in lots of places.
posted by Justinian at 11:50 AM on May 23, 2010


I think this is definitely a British thing, I'm from Scotland and this is really very common. I think usually news programs and weather channels would stick to the one standard temperature, but when people are just talking about the weather it's invariably Celsius for the cold and Fahrenheit for the hot.
posted by Spamfactor at 11:51 AM on May 23, 2010


@Justinian true it certainly seems in most places people don't have this little quirk. Judging by the answers Americans don't do this at all. As emyd said above it seems more common in Britain and Australia
posted by Spamfactor at 11:54 AM on May 23, 2010


I lived through the change-over from F to C in Australia--now I can work in either system, although I find low temperatures easier in Celsius--this is probably because when temperatures were in F in Oz, I was in Brisbane, where temperatures below 32F are pretty rare. During the changeover temperatures were given in both systems. I've never heard anyone use one system for highs and the other for lows.
posted by Logophiliac at 11:58 AM on May 23, 2010


39 degrees sounds plenty blistering to my Canadian ears.
posted by PercussivePaul at 12:09 PM on May 23, 2010 [2 favorites]


aubilenon, I'm surprised you heard this in the San Francisco area - I grew up there and never heard anyone use Celsius temperatures at all. As a data point, I've also lived in Ohio and Los Angeles, and never heard anyone use Celsius temperatures. Except in science classes.
posted by insectosaurus at 12:22 PM on May 23, 2010


I lived in the UK for almost five years and don't remember anyone other than Americans ever using degrees Fahrenheit.
posted by grouse at 12:34 PM on May 23, 2010


We don't see Celcius in Florida, but it may be the familiarity with 0 and 100.

100F is hot, and 0C freezes water. We understand those, with almost no thought about it.

32F and 35C isn't as easy to convey.
posted by cmiller at 12:42 PM on May 23, 2010


I'm British and I have, to my amusement, noticed myself doing this on lots of occasions. My thesis is that this is a hangover of the imperial/metric conversion. People who grew up with Fahrenheit understand what 70°F, 80°F, or 90°F feels like, whereas low temperatures tend to be easier to understand with reference to how near to freezing they are. It's easy to remember 0°C (actually 0.01°C) as freezing, but it is far less easy to remember 21°C, 27°C, or 32°C as the varying degrees of "hotness."
I also attribute this usage to the very British culture of pragmatism (and laisser faire), which dictated the use of metric units in 1973 (when the UK joined the European Union), but which took 22 years to enforce the conversion (1995) and which still has exceptions for road distances (miles), and for beer and milk (pints). Using our imperial system has benefits, as our cars get 20% more miles to the gallon than US cars ... :-)
posted by Susurration at 12:46 PM on May 23, 2010 [1 favorite]


Weirdly, I do the same thing. I've got friends and family that still use the imperial version and I've grown up all over the place. I know what 80F feels like, but it's hard for me to put that into Celcius. And I know what 0C feels like, but 35 or 40F means very little.

I know, it makes no sense. And I agree with DarlingBri: freezing should be 0 and boiling hot should be 100. Most of the time I love metric but 40C being hot doesn't make (emotional) sense to me.
posted by barnone at 1:40 PM on May 23, 2010


I'm British. When 38 °C it's reached, which is maybe every couple of years, I occasionally hear "100 °F". 32 °C is reached every summer, but I probably hear "90 °F" less than "100 °F". I don't think I've ever heard "80 °F" or anything less either on TV or in normal conversation. I think it's partly just the appeal of the round number one hundred, and partly that 38 °C/100 °F occurs so rarely than any change in the milestone we associate with "really, actually very hot indeed" is going to take more time to work its way through into normal usage.
posted by caek at 1:44 PM on May 23, 2010


I've lived in Australia 30 years, and never encountered Fahrenheit...It's such an archaic, alien concept to me, I wouldn't have the slightest clue of how to compare it to Celsius.
posted by robotot at 1:46 PM on May 23, 2010 [2 favorites]


I'm in the UK, was born in '79, and can honestly not remember the last time I heard anyone of any age using Farenheit.
posted by anagrama at 1:59 PM on May 23, 2010


A temperature "in the 90s" is often colloquially spoken about in the UK, simply because it sounds hotter than 32 degrees Celsius. In winter almost everyone uses degrees Celsius because everyone understands that 0°C is freezing.

Metrication happened in the UK in 1965, and with it came the transition to degrees Celsius. Some members of the older generation will always understand Fahrenheit and be able to relate to Fahrenheit better, hence why it is still used sometimes - though predominantly I think everyone understands Celsius well, it's just that saying that the weather is "in the 90s" has more impact and sounds hotter, especially since that kind of weather is relatively unusual in the UK.
posted by samengland at 2:06 PM on May 23, 2010


I know, it makes no sense. And I agree with DarlingBri: freezing should be 0 and boiling hot should be 100

well, that's celsius :) - just actually, technically boiling hot (which would be 212 F).

I remember reading that F was originally supposed to be based on human temps, though - that 100F is close to body temp and as hot as it gets, and 0 was approximately as cold as it gets / what might kill you. Apparently that's bunk, but it still kinda makes sense.

Between NY and London, I've never heard the usage you talk about - occasionally get both, but never one for hot and one for cold. Around here it gets cold enough to use 0F, so that would be confusing.
posted by mdn at 2:21 PM on May 23, 2010


New Zealand went metric in 1969, the year before I was born. I have never heard this kind of usage, although people my age sometimes still use feet and inches to describe someone's height. I have to look up the conversion formula for Fahrenheit (or these days, get Google to convert temperatures), I hear Fahrenheit so rarely. If it weren't for American recipes, I would never encounter it in daily life at all.
posted by i_am_joe's_spleen at 2:40 PM on May 23, 2010


Maybe because potentially hot, aka temperate, places, like the US, prefer the older scale while other first world countries — many of which are colder than the US — use Celsius because it's standard.

Maybe there isn't a reason because it's just personal experience. For example, I totally disagree that people do this in the UK. The only people I've ever heard talking in Fahrenheit are my grandparents and the Telegraph.

Maybe it's because those people who prefer to use Fahrenheit still have to be fluent in what it says on their fridges.
posted by westerly at 2:50 PM on May 23, 2010


I'm a relatively young (late 20s) Canadian, living in Ontario, and myself and my peers seem to use Celsius for the weather but Fahrenheit for body temperatures.
posted by purlgurly at 3:35 PM on May 23, 2010


Some folks do have a hard time with C to body feel temperatures. That's why I've developed the REAL FEEL temperature system. This is based on the number of layers of clothing needed to be comfortable. You can easily gauge what to wear based on this, or if you don't know what temperature it is but are comfortably dressed, you can derive a decent approximation.

Degrees Celsius = 30 - (Number of layers of clothing you need to be comfortable) * 10

Naked: 30C
T-shirt: 20C
T-shirt+overshirt: 10C
T-shirt+overshirt+jacket: 0C
T-shirt+overshirt+thermal layer+coat: -10c

If it's called a "parka" it probably counts for two layers.
posted by seanmpuckett at 4:03 PM on May 23, 2010 [3 favorites]


samengland: Metrication happened in the UK in 1965

Yeah but how metric is the UK really?

I know deg C is well entrenched now because that's what the forecasts on TV use and petrol is sold in litres but I wonder about other things. I was watching a rerun of Top Gear yesterday and Stephen Fry was the guest and said how he had lost six stone in weight. I suspect that if he had said it in kg then Jeremy Clarkson wouldn't have had a clue what he meant.

I often listen to BBC Five Live and people's height and weight sometimes come up and I don't think I've ever heard an "ordinary person" caller use metric. A medical person guest was once talking about babies' weight using kg and the host had to ask several times "what's that in pounds?".

If the average Brit was asked for give his height, would it naturally be given in feet and inches or cm?

I think the roads are still in miles.

I get the impression that metric in the UK is more a matter of official correctness than reality for most people but ... I haven't been there so I might be wrong.
posted by tetranz at 5:05 PM on May 23, 2010


I am completely aware that from a science perspective, this makes NO SENSE. I don't care. Cold is 0 and hot is 100. Yes, my husband despairs.

It makes perfect sense, it's just not a scale anybody uses. The Celsius and Fahrenheit scales have nothing to do with the universe and everything to do with people just making up ways to measure temperature; you could just as easily start using a scale in which 0 is freezing and 100 is equivalent to 100 degrees Fahrenheit if you wanted to -- but at this point, it's probably too late for a new scale to catch on.
posted by magnificent frigatebird at 5:39 PM on May 23, 2010


Canadians who spend any significant summer time in the US often do the cold C/hot F stuff -- I have a great grasp of water temperatures in F, but not in C, though I am ok in air temp for both.
posted by jeather at 5:47 PM on May 23, 2010


fyi, In my 29 years I have lived in QLD, VIC, ACT and NSW in Australia, and I have _never_ heard anyone using fahrenheit, anywhere.
posted by smoke at 6:02 PM on May 23, 2010


I'm from the UK, but moved to the US several year ago. I am very familiar with this concept, its how my internal mental temperature gauge works. I agree 100% with DarlingBri, its completely illogical, but it makes sense!

I think this mental model is only found in UK residents over a certain age. I was born in 1972, so I spent my childhood learning about metric units in school, and came home to imperial units for everything. I'm trapped in a weird unit purgatory. Now I'm in the US which is steadfastly refusing to enter even the 20th Century when it comes to measurements, and so the madness continues.
posted by Joh at 10:10 PM on May 23, 2010


Also, that temperature range of 0 Celsius to 100 Fahrenheit pretty much describes the UK's weather. It does drop below 0, but not very far below, and not terribly often. Its very rare that it gets to 100F, but it gets to 80F in summer, and can climb higher. Hence the mental model.
posted by Joh at 10:12 PM on May 23, 2010


Interesting. I have lived in several countries, and have heard people using both C and F - but these are usually different people, in different countries.

The idea of confusion in places where the systems haven't yet changed completely makes sense.
posted by vidur at 10:53 PM on May 23, 2010


I do it because I lived in cold, Celcius-using countries when I was a kid, and hot, Farenheit-using countries when I was older.
posted by The corpse in the library at 9:36 AM on May 24, 2010


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