Breath of the wild Fahrenheit/Celsius
There's no in game option to change it.
American version
- Temperature is Fahrenheit
- AM/PM Clock 12:00 - 11:59 am/pm
European version
- Temperature is Celsius
- 24 Hour Clock 0:00 to 23:59
some stupid workaround:
Use an account tied to a different region, or change the consoles region.
EDIT :
It seems you have a hardcopy version of the game which mean there is nothing you can do except buying EU version of the game.
Easier Way :
(°F - 32) x 5/9 = °C