@atoponce While there was some fiddling, normal body temperature was set to be 98.6 degrees F, which is 37 degrfees C,. and 0 degrees F was the freezing point of a specific mixture of water and a salt (ammonium chloride). It might have made sense in the 18th century.

The Fahrenheit scale is used in the U.S. for the same reason that country still uses inches, feet, and pounds: if it was good enough for grandpa, it is good enough for me.