I worry about my engine stalling regardless.

I've flown to -10º, but was more worried about the Monokote than the electronics. They're solid state and, allowing for the batteries to be a bit draggy, are unaffected by temperatures you could stand exposing your thumbs to. The covering, however, seems to become very brittle. We fly on January 1st regardless, and usually have several winter "Chili" flys throughout.