Celsius scale:
Excellent UI. Very sensible. Water freezes at 0 and boils at 100. Nice.
Poor UX. Not enough value range between dangerously cold vs. dangerously hot for the average user experience.
Fahrenheit scale:
Poor UI. Arbitrary 0 and 100 points. Water freezes at 32 and boils at 212. wtf.
Good UX. The 0 and 100 points are sensible danger cold/hot indicators for everyday average user experience.
Kelvin scale:
Good UI. 0 is Z E R O. Absolute. Unit spacing is equivalent to Celsius scale. Indicator of absolute thermodynamic energy, excellent for scientific purposes.
Terrible UX. Everyday user experiences are in the upper 200s. Only usable by scientists and engineers. Does not use the degree symbol, because it is a literal unit of thermodynamic energy and not a temperature scale. Not immediately intuitive.
Rankine scale:
lol
wtf
This is just the Kelvin scale but for Fahrenheit.
Except it uses the degree symbol unlike the Kelvin scale. wtf
Absolute zero is -459.67Β°F
Delisle scale (yes it's a real scale):
wHaT tHe fUcK iS tHiS UI???
0 degrees is the boiling point of water
150 degrees (POSITIVE) is the freezing point of water!!!
This scale goes fucking BACKWARDS!!!
Acceptable UX for its time:
Joseph-Nicolas Delisle invented this scale in 1732 when working at an observatory he founded in St. Petersburg, and wanted a temperature scale appropriate to Russian winters.
Higher temperatures == more dangerous cold!
Footnote
There are more temperature scales than just the five I covered here. I just wanted an excuse to compare Fahrenheit vs. Celsius and their absolute zero counterparts, and a bonus scale that makes me gremlin cackle anytime I bring it up!
Check out a more complete list, here!