What is the boiling point of water in Fahrenheit?

212, which looks arbitrary because it is. Daniel Fahrenheit built his scale from other reference points entirely: zero was set by the coldest temperature he could reliably reproduce, a slush of ice, water and ammonium chloride, and the upper part of the scale was pinned near human body temperature. Water's freezing and boiling points landed where they landed - 32 and 212 - as consequences rather than choices.

The 180 degrees between them is the one elegant thing about it, and it is probably not an accident: 180 divides evenly a great many ways, which matters if you are making thermometers by hand and subdividing a scale with a scribe. Fahrenheit was a glassblower and instrument maker, and his real achievement was mercury thermometers consistent enough that two of them agreed - which was not true of anyone else's at the time.

It survives in the United States, and the usual argument for it is that its degrees are finer and its everyday range maps neatly onto human comfort from 0 to 100. That is a fair point about weather and a poor one about everything else, which is why American science, medicine and industry all use Celsius while the weather forecast does not.