Yeah, neither did I... but hold down both the + and - buttons for 3 seconds and the LCD will light up completely and it will toggle between Celsius and Fahrenheit... be careful when doing this because it also resets the set temperature back to the factory default (38˚C or 100.4˚F) so be prepared to make adjustments if you change yours.
This little tidbit isn't in any manual/instructions I've been able to find.... weird.
This little tidbit isn't in any manual/instructions I've been able to find.... weird.