Obviously a significant proportion of our audience (namely in the United States) prefer °F over °C, whereas the rest of us work in °C.
If a question or answer features temperature, usually the author will only use his preferred measure.
Possible approaches:
a) seek to always edit in the translation so that all content here has temperature in both °C and °F
b) editing the odd question where temperature is the main point of the question/answer and/or editing questions you are interested in as and when you find them
c) leaving the post in the author's original preferred measure
For example, in today's question How low (and for how long) does the temperature need to be before I need to worry about covering my outdoor vegetable garden? I can't get anything valuable from it until I've translated it into °C and if I'm doing that, shouldn't I edit it in for other visitors?
Any thoughts? Does anyone know what they do at Cooking?