MN Winter Phenomenon

It's amazing the things you don't realize until you move from the hottest part of the country to the coldest. It wasn't until sometime this winter that I realized that when it was really cold outside, I didn't have ice form on the outside of my window... it was on the inside! The winter here isn't drippy wet snow and rain and stuff. It is sub-zero temps, high winds, and almost no humidity. It dries out my skin faster than a 120 degree day in Phoenix. So, it did make sense that the ice wouldn't form outside, the condensation inside will freeze on the window panes. When it goes away I think it more sublimates than anything because I don't ever find small puddles of water on my window sill.