I'd have to look it up, but I don't really care to be honest. Celsius is the way it is because it was designed around the phase transitions of water, which is all fine and good, but logic is a nonfactor when you already know that water freezes at 32° and boils at 212°, that average room temperature is 72°, and the average human body temperature is 98.6°. Aside from freezing and boiling, I couldn't tell you for sure what anything else is without having a calculator and the conversion factor to figure it out. I think average room temperature is around 23°C, but I don't know for sure. The metric system simply isn't practical for a lot of the ordinary, everyday things I do. In terms of weight, grams is too small, and kilograms are too big, while pounds are at a nice happy medium. The same goes for measuring height, as mm, cm, and even dm are too small to be practical, and meters are too big, but feet and inches work out pretty well for that. When it comes to driving distance, miles works very well, because kilometers are frankly too small IMO when it comes to that, especially when it comes to measuring speed and fuel efficiency. This of course completely ignores that the lay of the land literally reflects the imperial system of measurement, because land is divided into sections that are each one mile by one mile, with a road to mark the vast majority of the section lines. Liters are too small unless you're talking about something you might drink (gimmie a liter of cola), whereas gallons are much more practical for measuring larger volumes of water.
On the other hand, I prefer the metric system for scientific and engineering calculations, mainly because I have most of those constants memorized. While I know the acceleration due to gravity is 32.2 ft/sec in the Imperial system and 9.81 m/sec in SI, I don't know what the speed of light is in ft/sec, while I do know that it's 3.0x10^8 m/s in SI, R is 287 kJ/kg/K, etc. Gas turbines has made me memorize a few more of what is now apparently being referred to as the "United States Customary System", but I still prefer metric for that kind of stuff simply because I have more memorized for those types of calculations in SI.
Edit:
All you never really wanted to know about the origin of the Fahrenheit scale