YOu are right. I have never seen -30* weather. The coldest its ever gets in NEPA is 0. But then again where does it get to -30 in the US?
Not sure, I've seen -24 in Clare once. It's kinda funny when I went to Farwell schools they would cancel school if it got under -20, then when I moved to Clare they would cancel if it got under -15, by the time I graduated they moved that temp up to -10... F*ing pansies that run our schools.