If you grew up in America, you know that when the thermometer reads 32° F it’s time to bundle up, and if it’s 85° F outside you should break out a t-shirt. But say these temperatures to someone living in a different part of the world and you’ll likely be met with confusion. That’s because the United States joins Myanmar and Liberia as one of only three nations that don’t recognize the metric system.

In its new video, Vox explains why the U.S. is still measuring degrees in Fahrenheit long after the rest of the world decided to make the switch to metric. It wasn’t for the government’s lack of trying: In 1975, the country passed the Metric Conversion Act with the intention of selling the system to Americans. But while Canada, the UK, and Australia made adopting metric measurements mandatory, there was no such enforcement in the U.S. So, given the option to stick with what they know or teach themselves a whole new system, U.S. citizens chose the former.

To learn about the history of Fahrenheit and Celsius, and to see how the imperial system is more than just a nuisance for people visiting the U.S., check out Vox’s full report below.

[h/t Vox]