Why the US Still Uses Fahrenheit Instead of Celsius
If you travel anywhere outside the United States, the weather forecast will look incredibly alarming. A forecast of "30 degrees" sounds like a freezing winter day to an American, but to a European using the Celsius scale, 30 degrees is a blisteringly hot beach day.
The United States is one of only three countries in the world (along with Liberia and Myanmar) that still officially uses the Fahrenheit scale for temperature.
But why? And how did we end up with such a seemingly random scale in the first place?
The Invention of Fahrenheit
The Fahrenheit scale was invented in 1724 by a German physicist named Daniel Gabriel Fahrenheit. At the time, there was no standardized way to measure temperature.
Fahrenheit wanted a scale that avoided negative numbers as much as possible for everyday weather.
- He set 0 degrees as the absolute coldest temperature he could artificially create in his lab (a freezing mixture of water, ice, and ammonium chloride).
- He set the human body temperature at roughly 96 degrees (he was slightly off, it's closer to 98.6).
Based on those two anchor points, the freezing point of plain water naturally fell at 32 degrees, and the boiling point of water fell at 212 degrees.
To the rest of the world, 32 and 212 seem like completely random, arbitrary numbers.
The Simplicity of Celsius
Nearly 20 years later, an astronomer named Anders Celsius proposed a much more logical system. He anchored his scale directly to water, the most abundant resource on Earth:
- 0 degrees = The freezing point of water.
- 100 degrees = The boiling point of water.
This base-100 system was so clean and logical that it was universally adopted by the scientific community, and eventually, the rest of the globe.
Why Hasn't the US Switched?
In the 1970s, the US government actually tried to switch to the metric system (including Celsius). The Metric Conversion Act of 1975 was signed into law, and road signs displaying Kilometers even started popping up.
However, the change was made voluntary. The American public, largely accustomed to their own system, violently rejected the change. Repainting every speed limit sign, changing every oven dial, and retraining millions of citizens was deemed too expensive and confusing. The effort was quietly abandoned.
Today, Americans fiercely defend Fahrenheit for weather forecasts, arguing that a 0-to-100 scale perfectly represents the human experience of temperature: 0 is incredibly cold, 50 is mild, and 100 is incredibly hot.
Master the Conversion
If you are traveling abroad or reading a recipe from an international blog, you must know how to translate the temperature.
Skip the complex fractional math and simply use our free Celsius to Fahrenheit Converter to instantly jump between the two scales!