Condensation in Cabin? Normal?

OP I reread the first post about the above and below freezing, the below freezing I was thinking below zero, I'm used to cold temperatures, those you are talking about when I was younger we were dam near tee shirt temperatures. But they are probably the worst for humidity and condensation someone mentioned 87% humidity , tropical type conditions in cooler conditions. Up north I go into a new home and people are complaining there locks and windows have a 1/2" of ice build up inside the home the temp is 70 outside -20 humidity at 64% + and they won't by it that that is the cause @ -20 the recommended humidity level is 20% they are destroying the windows and out side locks let alone providing great conditions for black mold to form between the walls and behind the sheet rock.

 

One last thing check to mack sure your back window is fully closed.