#celsius

Namely, the temperature at which water starts to boil.

It's the biggest argument people always have for why Celsius is better, but it only really applies at sea level/standard atmospheric pressure.

So, there are places that use Celsius because their colonizers did. This includes

Mexico: In Mexico City, water boils at about 92.56 C

Bolivia: In El Alto, the second-largest city, water boils at 85.9 C

Ecuador: In Quito, the second-largest city, water boils at 90.47 C

Colombia: In Bogotá, water boils at 91.26 C

Ethiopia: In Addis Ababa, water boils at 91.67 C

And so on.

(I used this Wikipedia page to find cities with over a million people and their average elevations, and I used this calculator to find the boiling points. Unsurprisingly, most of the high-altitude cities of size are in South/Central America.)