Originally Posted by
Gladiator
Frostbite, not breathing, is the main problem in low temps. If it is windy it does not even have to be very cold to do damage.
It doesn't have to be windy for there to be significant windchill. We are, after all, on bikes and creating our own "wind".
That said, it'll get uncomfortable for you long before you're in danger of frostbite.