I grew up in Duluth Mn., and I certainly know what sub-zero weather feels like. When we were kids, I can remember going out to play when it was -20 or -30*.
Whether it's -20, or -50, when it gets that cold, it really doesn't feel any different. Frost bite in less than 5 minutes on exposed extremities! That's the main reason I left Minn., and moved to Utah. We still have 4 seasons, but a much Shorter, and Milder winter. High of 48* today
