We'll be doing it in caves before long, if present trends persist.

Celsius is useful if you're a beaker of water. Fahrenheit is useful if you're a human.

Humans cannot reliably determine the difference in one degree c, even though it's bigger... Fahrenheit is too fine grained, and has no interesting points relative to the things I interact with. I freeze an boil water often, however

This is false. I frequently find myself annoyed at my AC because it only has settings of 72°F and 74°F, and they are a little too cold and a little too warm for me. I want 73°F. When it's around room temperature, you can absolutely tell the difference.

The further away from room temperature, the less we can distinguish. All our senses work logarithmically like that.

I grew up during the F to C transition in the UK and F is not intuitive.

0 = ice 100 = steam

That is pretty intuitive if you ask me. And for gravy comfortable room temp is about 25

Fahrenheit is sort of intuitive if you think of it as somehow, impossibly, a percentage scale. 0C/32F is still decently comfortable anyway. 0F is, like, not at all comfortable. 100C is dead. 100F is the most unbearably hot temperature that isn’t immediately deadly.

100°C is somewhat uncomfortable, and it usually indicates that someone is trying to show off. 80 to 90 is much better. (In a sauna.)

Just curious on what planet you exist where 100C is only “somewhat uncomfortable”

It does kinda depend on humidity, fwiw. In New England, the 90’s are hot, unpleasant sticky weather.

I guess it doesn’t happen often, but I saw some upper-90’s temperature in the Portland, Oregon area. It feels relatively mild actually, compared to New England 90’s, I’m pretty sure because it is so dry. The lighter air just carries the heat away, rather than having it stick to you.

I think GP was talking about saunas and not ambient temperature. So 100C not 100F. Still the argument remains the same: Low humidity (and reasonably short durations)

Oh jeez, I totally missed the C, haha. Silly of me given the topic of the thread.

Our maximum day time tempreture in January 2025 was 113 F ( 45 C ), 12 days or so were over 100 F ( 37.7 C )

http://www.bom.gov.au/climate/dwo/202501/html/IDCJDW6136.202...

This is in the cooler south west corner of a large state ( 3x size of Texas )

Of course, the experience of heat does depend on humidity as well. But, how was it? It sounds… too hot!

Fahrenheit is very intuitive if you are in Danzig in one particular year... [0] otherwise.. It's a historic accident. If you want to root your measurement system in human experience your measurement system will be outdated in a couple of decades. Because humanity changes! That way there will always be old/antiquated/historic units. Metric basically accepts that and uses easy to convert units and leaves the intuition forming to the humans gathering the experience

[0] Apparently the story is disputed.. But the way I was taught it was: 100F == typical healthy human and 0 F == lowest temperature in Danzig in the winter 1708/1709. This makes it (by construction) a more natural fit to human experience (especially one in northern Europe) https://web.archive.org/web/20131015045624/http://www.deutsc...

It's missing one important distinction: Below 0C: Freezing, probably slippery, not raining water. Above 0C: not freezing, probably not slippery, rain comes as water. They are as uncomfortable as you make them.

The base units of the metric system are often not very ergonomic. Why is a meter so damn big? And why is a gram so damn small? I can barely detect a gram. And a meter is frickin huge, causing people to usually divide it into hundredths of a meter, which you can hardly picture in your mind unless you already know what it looks like, especially arbitrary counts of cm. Metric's only real advantage is that it shares the same radix as our counting system.

What we really need is a new system of units...

As a metric user: This is about your lack of familiarity.

E.g. can picture lumber expressed in cm or mm very easily. E.g., if you work with beams that are 48mm / 5 cm or 98mm / 10cm a lot then those sizes becomes second nature. Just as easy to picture as 2 inch, 4 inch, 1/2 inch, 3/4 inch etc that is in use in US.

And saying that something is 200m away is exactly as intuitive as however many feet that is. A large meter has a usecase.

I feel square metres for houses is very natural unit and square feet sounds awkward (each patch of house area is so small you can do nothing with it, a square metre gets you somewhere..).

Making yet another system of units sounds like massive pain and as someone who are used to metric I see no advantages.

As a user of both Imperial and Standard International units, I agree with you.

As a kid, one of my science educators spoke about the many benefits people gain from becoming familiar with basic units. I bought in and did so during the big metric push that happened around that time.

I ended up more familiar with Imperial units.

Then, later in life, I entered a young industry, with strong users of metric, Standard International units.

So I did the work to build familiarity just as I did long ago. Took half a year and today I enjoy the benefits.

And those are:

Ease of understanding unit values meaning in my daily life.

Ease of expression of same to others.

Greater accuracy estimating.

Easier computation and unit checks.

And so on...

Ah but are 48x98s nowhere near 48mm and 98mms like our 2x4s?

48x98 is exactly that dimension (i..e after planing of the lumber). Well, +/- 1 mm of tolerance/shrinkage due to drying.

It goes by the name "two four" here as well informally due to long tradition (and yes, I once did wonder why 2-by-4 is smaller than 2 by 4 inches and looked it up), but you will not see it written anywhere, in writing it is always in mm after planing.

The oral words for lumber dimensions before planing is the only context as an adult I have met inches except in US.

Using metric has never been an issue in trades or sciences in metric countries.

A metre is much the same as a yard or an adult arm span. Not a problem.

Pretty much all carpentry and cabinet making is done in mm alone, the width of a fat pencil mark.

1400mm is shy of a metre and a half (1500mm), cross piece spacing might be 300mm (about a foot).

No need to have feet, inches, quarters and thirds mixing up the page, just use mm everywhere.

A gram is fine for small mass measurements, a kilogram is a good unit for heavier masses - very human scale being the same as a litre of water and more or less a litre of milk.

It really comes down to familiarity, there's nothing intrinsically difficult about metric (and much that is more intuitive than odd imperialial units and the whacky intra unit conversion factors).

As a metric user, this is an interesting point that I haven’t heard before, and I think the other responses don’t really engage with it. Yes, familiarity means this isn’t much of a daily problem – you just use divisions of the unit that are most appropriate. But the size of the base units for volume, mass and length don’t really match up well from a human day-to-day perspective.

Wouldn’t it be nicer if a litre, a gram and a cubic metre of water were equal, rather than 1 cubic metre, 1000 litres, 1,000,000 grams?

Side note that in Europe drinking products are often labelled in centilitres whereas Australians use millilitres. I wonder whether this indicates some difference in the way the two groups think about volume, or maybe it is just the fallout of some other constraint, like translations limiting the space available.

Still, the ergonomics seem to be on the side of Metric, taking into account the ease of conversion between units when all are base ten.

Nah, Celsius is useful if you're a human. Fahrenheit is useful if you're an American.

If you are used to Celsius, sure. But the point the op was making is Fahrenheit was designed with humans in mind and Celsius with the changes of the state of water. Your average person didn't really care what temperature water boils at, just that it is hot.

> Fahrenheit was designed with humans in mind

If there was a design, it's not clear what the intent was. It seems about twice as precise as it needs to be (i certainly can't perceive 1F°—for all intents and purposes, 70 feels about the same as 69 and 71) and doesn't seem to correlate to any scale that is immediately based off the needs of humans. At least compared to celcius.

Farenheit set 100F to be his wife's internal temperature. 0F was the freezing point of brine and humans are mostly brine. F is human centric.[0]

[0] https://en.wikipedia.org/wiki/Fahrenheit

He says in his original paper that the top point of his reference scale is 96, not 100 for the point where "Alcohol expands up to this point when it is held in the mouth or under the armpit of a living man in good health". He originally based his scale on 12, and then got more precise by increasing each division by two several times, ending up with 96.

So basically, Fahrenheit chose 100°F to be the temperate when he gets hard and 0°F to be the temperature when his wife gets hard?

This is very interesting, because I absolutely can feel one degree F difference in house temperature.

I wonder if using a lower resolution scale dulls the senses like other forms of https://en.wikipedia.org/wiki/Linguistic_relativity

I live in the US and can't change my thermostat, so I don't think that's it.

I'm sure I could feel the difference if i split myself between two rooms with one degree difference. I just don't think this is a useful granularity—I typically move the thermostat by 2-5 degrees at a time.

0F .. 100F is about the range of temperatures a human living on earth could reasonably expect to experience without deliberate adventuring. It's not a precise range - plenty of people live in Doha (way above 100F) and in Alberta (way below 0F) - but it's a pretty reasonable approximation.

I'm not convinced the people of Doha or Alberta would consider their day to day lives adventures

My comment ends with a note that "it's a reasonable approximation".

The percentage of global population where the 0F..100F range is not a reasonable approximation of the temperature range they will experience is small. It's not perfect - no such range could, when humans live almost everywhere on the planet. But it's not bad ...

No, Fahrenheit was not designed with "humans in mind".

Neither 0F nor 100F are anything special for humans. It's "very cold" long before 0F and "very hot" long before 100F. 50F is nothing special either.

Room temperature is 72F.

Who needs 2x the effective resolution at human temperature scales? Or useful temperatures without significant digits beyond the decimal?

Agreed, there's a reason most of the world uses it.

0 is cold as fuck, 100 is hot as fuck. Perfect human scale. Stay jelly

-40 - cold as fuck, 40 - hot as fuck. 0 - shit freezes, better drive carefully.

I don't understand why this is always breought out when farenheit is criticized, as if the 0F-100F thing is the "killer app" for temperature scales.

As an American I’m biased, but Fahrenheit matching the 1-100 scale used in so many other things just feels nice. Maps cleanly to 0-1.0 in a float/decimal type in programming which is neat too. Feels less arbitrary even if it actually isn’t.

I prefer metric otherwise but for temperature Fahrenheit just “clicks” in ways that Celsius doesn’t.

Fahrenheit doesn't match the 1-100 scale, though - Celsius does. 0 water freezes, 100 water boils.

Herr Fahrenheit measured the temperature many times over a period of one year in some town in Germany. He defined 0 degrees as the coldest measurement, 100 the hottest measurement.

Ok but Celsius works wherever you are (adjusting for pressure)

> some town in Germany

The Polish city of Gdańsk, of the then Polish-Lithuanian Commonwealth. He was also born there at the time. [1]

> He defined 0 degrees as the coldest measurement, 100 the hottest measurement.

Nope. It was neither about the temperatures in Gdańsk, nor about the temperature of his wife, btw. ;) [2]

  [1] https://en.wikipedia.org/wiki/Daniel_Gabriel_Fahrenheit
  [2] https://en.wikipedia.org/wiki/Fahrenheit

In what country do people encounter -40 degrees

Russia, canada, sweden, norway, finland, us... probably missing a few. Edit: mongolia too, I think.

curiously, nothing in the southern hemisphere?

Antarctica

We had a -40F windchill day here in Michigan a few years ago.

-40°C feels pretty much the same as -40°F

Because it is the same.

Parts of Canada for sure. When it’s below -35C my garage stored vehicle’s cold engine light turns after a bit on while driving!

Anytime your scale has to go into negative numbers to represent common scenarios, it's not human friendly.

If you're not tying your scale to human-specific temps, why not just use Kelvin? At least that won't go negative.

20F is also cold as fuck. 90F is also hot as fuck.

30 is hot.

20 is nice.

10 is cold.

0 is ice.

Not hard to remember for converting Celsius to how humans typically perceive temperature.

My problem isn't remembering the scale, it's that Fahrenheit offers me double the effective resolution and descriptive accuracy without awkward decimal points in the numbers used.

I like my room at 73F, not 72F or 74F, and I can feel the difference. That's 22.77C. :-/

My main observation in temperature scale and imperial lengths discussions om the Internet is that Americans seem to have a strange aversion against fractional parts of numbers, as if those were irrational.

(On the other hand a lot of Americans consume fava beans.)

Au contraire base 12 measurement is _all about the fractions_. 12 can be divided evenly by 2, 3, 4, and 6. Metric gets 5 and 2. By that measure it's y'all that are afraid of the small numbers.

US units are pinned to Metric standards anyway. We're just using the most creative ratios. :)

Most temperature sensors are accurate to 0.1C. Most weather forecast is 0.5C resolution. So yeah only explanation to Americans behavior is an aversion against fractional numbers as you said.

I found this take from 'Torque Test Channel' (tests battery tools) humorous: https://www.youtube.com/watch?v=2QUum9NymZY

Brilliant and hilarious.

American, I think we use fractions all the time: 7/8 inch hardware tools, 3/4 measuring cup in cooking, etc. Especially awkward when you have human distances, because you have to mix feet + inches: 3 feet 4 and 1/4 inches.

It was a dream once I got a metric tape measurer and realized that using centimeters eliminates the need to do annoying conversions.

I like my room exactly at 21C. Any F number is Greek to me.

Remembering is more about what you are used to here.

> I like my room at 73F, not 72F or 74F, and I can feel the difference.

I suspect you wouldn't notice if it changed by a degree.

You'd be wrong. Happens.

I might be, but I don't think so. It certainly happens less often than something like people making ridiculous easily disprovable claims.

Cool yeah let's compress the entire scale to 0-35 and waste the other 65 up to 100 lol yeah what a great scale

The "entire scale" has no maximum. So your waste of the Celsius scale from 35-100 is Fahrenheits waste of the scale from 0-32 or whatever you're trying to base your comments on.

Perceiving temperature involves dew point and relative humidity, not just temperature.

Okay. Or, hear me out.

On a scale from 0-100, you have very cold and very hot.

Or you’ve got from 0-45. Where 0 is “meh” cold and 45 is incredibly warm.

So you’ve got a nice little 0-100 scale that all humans are going to experience just living that goes from very cold to very hot.

Or you’ve got a useless 0-100 scale that the bottom just means freezing, and ignores every pain point of being really cold below that, and anything really greater than 50C only has practical applications in cooking.

0 isn't the bottom of the celcius temperature scale, there are negative numbers

What significance does 0°F have to a human?

0°F was the outside temperature with 40 mph winds (60mph gusts) the time I had to venture to the middle of an empty field to break the ice on water tank with a hatchet so cows could get water.

I thought at 0°F you're supposed to bring the cows inside! Also at 100°F

I guess it depends on the cows

This was in the Texas Panhandle, temps this low are abnormal. Cows can survive this temps as long as they have adequate feed and water. They can endure high temps pretty well, again as long as they have water.

Exactly. Where I live we have temps from -20F to 110F, which is -30 to 43C. Idk, seems to me the hottest normal temp being 90ish and coldest normalish temp at 0 is a decent scale.

?

It’s cold.

Why? Celsius is just as arbitrary a choice as Fahrenheit. It brings nothing extra to the table. You might as well complain that tapered pipe threads are in US inches or that astronomers use AUs and light seconds rather than meters.

In Science, global standards matter. Such as Metric and Celsius.

Fahrenheit and Celsius are defined perfectly with one another so are as easy to convert as using a different number base though. And both were originally defined at arbitrary points making neither one better suited than the other at really anything.

If they used an absolute scale like Kelvin, then sure it would be an objectively better standard, but Celsius has been defined via the Kelvin scale for over 70 years now, the same as Fahrenheit.

What makes you think the research was done in Fahrenheit? This is a blog post by a science communicator who’s trying to reach a wide audience of American-English speakers. It stands to reason that they’d use units that their audience is familiar with.

So, Kelvin then?

Sure, 273.15K ± something.

Units gatekeeping/purity testing is the most pathetic "I'm more smart than you" bullshit ever.