Video: Like most ways of measuring things, the United States uses a different temperature scale than most of the rest of the world. However, the Fahrenheit scale often doesn't make much sense compared to the Celsius scale. This video explains why.
As the video above explains, before Celsius or Fahrenheit became standard, getting precise tools to measure temperature was a bigger problem than the scale that temperature was measured on. Daniel Gabriel Fahrenheit was one of the first to use mercury in his thermometers and his tools were reliably accurate. This was a new development at the time, so his thermometers were quickly adopted.
The scale, however, was pretty arbitrary. Fahrenheit kept his formulas secret, so we don't actually know exactly how he determined where zero should be on the thermometer. Allegedly, zero was supposed to correspond to a salt, ice and water mixture, with 100 degrees being the temperature of a human body. Neither of these is strictly accurate, but at the time that didn't matter. What mattered was that the thermometers were consistent. Now, we have better tools to measure with, and so we've adopted the more intuitive Celsius scale that sets zero as the freezing point of water and 100 as its boiling point, with the human body temperature set at 37 degrees.
What the Fahrenheit?! [Veritasium]