Originally Posted by
wphamilton
A difference of 10° F is nine fifths the difference in Centigrade, as you already know
5.6°C
Your question made me wonder, maybe for the first time, why on earth Fahrenheit normalized his scale at 32° for freezing. It turns out that he just used the earlier Roemer scale, which was based on an alcohol thermometer, and multiplied everything by four, later adjusted by a couple of degrees for a more accurate mixture of ice water. So, basically arbitrary and almost random.
We like it better though. Zero is terribly cold and 100 is uncomfortably hot, it works pretty well for that, more of a metric scale than Centigrade from that perspective.
Not really random. As you note, 100 is a very high temp an 0 very low. In fact, it's based on the highest and lowest normal European temps and very useful as a human temperature scale. Who really cares where water boils or freezes and, in any event, those actual number depends on many factors such as air pressure and dissolved minerals. And you can't divide or multiply temps so the "metric" thing is mostly irrelevant.