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.