What’s Up With the Title?

The 1991 Ballentine edition of this book made the meaning of the title pretty obvious with an addendum to the title: "Fahrenheit 451…the temperature at which books burn." This is followed shortly by: "The novel of firemen who are paid to set books ablaze." That pretty much covers it. Our only question is what they call the book in countries that don't use the Fahrenheit temperature scale. Celsius 232.778?