How to use flint in Breath of the Wild

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

When you read his diary, it mentions that the name of the dish is spicy meat and seafood fry. That's the clue that the last ingredient is fish.

Also, you don't have to specifically use raw meat. I was able to make it with raw drumsticks instead, which is a lot easier to get. I think it just has to have something spicy, some kind of meat, and some kind of fish, all of which is pretty obvious from the name of the dish.