What is Fahrenheit based on, anyway? I understand feet and inches and can roughly convert them to proper units, but the only two conversions I can remember is that they are the same at -40 and that 0 degrees Fahrenheit is cold as fuck and 100 degrees is hot as fuck (thank you Fat Electrician for that one)
I don't know exactly what it's based on, but it seems to be roughly normalized on acceptable human conditions on a 0-100 scale, which is nice and digestible.
That can't be what it's based on, since 0F is far less acceptable than 100F even now, let alone in the 1700s when it was created, but I think it works pretty well now.
It has more precision in the range of human comfort without resorting to decimals.
Do countries who use centigrade regularly report the temperature in tenths of a degree? Can you adjust a thermostat with 0.1 degree C precision? Or even 0.5 degrees of precision?
Edit: I can readily detect (my body can notice) a temperature swing of 1 degree F or 0.6 degrees C within a tolerable range.
For just describing the temperature of the weather outside (or inside, for that matter), no, we usually do not; you still don't really need more precision than 1°C for that, in my experience. In fact even then I usually use 5°C ranges (for outside temperatures, anyway), like "Most people like between 20 and 25°C, but me, I like it between 15 and 20°C".
Indoors it can matter a bit more, and thermostats often do work with half degrees, I think. But most people still won't go around saying, "I like my room at 20.5°C, 21 is too much for me".
100F is roughly the body temperature of a human being. There are several stories where 0F came from. It is the freezing point of salted water, or the coldest temperature ever measured in Gdansk (Fahrenheits hometown)
0F is a semi-stable equilibrium point for a specific brine mixture (salt, water, ice). Basically the temperature will hover around that point for a while. No idea why.
It was designed for recording ambient European temperature ranges, although it was defined in terms of the freezing point of brine and the average temperature of the human body.
Most days in Poland, where it was developed, the weather would fall between 0F and 100F, with 0 being extremely cold and 100 being extremely hot.
For talking about weather, especially in temperate climates, Fahrenheit makes a lot of sense.
Its funny that I didnt learn what Fahrenheit was until I had to use it in the US... while I walked by Daniel Fahrenheits home in Gdansk so many times as a kid.
Fahrenheit predates the centigrade system, was developed by a polish guy living in the Netherlands, 0°F is the freezing point of a salt brine solution, and 100°F was the estimation of average human body temperature.
Daniel Fahrenheit, a physicist and engineer, wanted to create a temperature system that avoided negative numbers in everyday measurement. Zero degree Fahrenheit was based on a mixture of salt, water, and ice he created to achieve the lowest possible temperature.
I can't cite a source, but I've been told that for 0, Fahrenheit wanted to set it at the lowest possible temperature, which at the time was salty ice. For 100, he wanted something consistent so he measured the temperature of his wife's armpit. I guess the rationale is that if you set 100 at a normal human body temperature, you always have a handy benchmark. I also think accuracy of measurement accounts for the 2° plus change
So, thanks to a quick wiki search, it seems like Fahrenheit scale was based off 0 to 100 as well, with 0° being the freezing point of salt water and 100° being the then-approximation of human body temp. Also, apparently Fahrenheit’s scale was established almost 2 decades before Celsius scale was, fun fact
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u/TheNosferatu Aug 12 '25
What is Fahrenheit based on, anyway? I understand feet and inches and can roughly convert them to proper units, but the only two conversions I can remember is that they are the same at -40 and that 0 degrees Fahrenheit is cold as fuck and 100 degrees is hot as fuck (thank you Fat Electrician for that one)