Blackrat
He Who Lurks Beyond The Veil
I think the implication is that when the high for a day is -10 C, that's a cold day in Moscow. Because otherwise, -5 C is just barely below freezing. On a cold morning, Phoenix can be nearly that low, let alone Boston. But Phoenix will always climb above freezing as the day warms up.
No that's pretty average winter day for the whole day around here. When it's cold day it's around -20 for the warmest part of the day.