A Ren'Py wizard somewhere should add a new toggle in the options menu, like the translation choice: Imperial or Metric. Then devs on either side of the pond can write in whichever units they are comfortable with and the player chooses which they understand and the game translates the dialogue. Just to avoid the discordant hiccup in the brain when someone accustomed to imperial reads about people being sweaty at 28 degrees

(which is below freezing for us cave people who haven't accepted metric yet. Don't worry, we'll get there in a decade or two.)