Question

If you park your car next to a woodlot overnight, the end of your car facing away from the woodlot may be covered in frost, while the end facing the woodlot may be free of frost. Explain this phenomenon.

Answer 1

Whereas, under a carport, the top of the roof will cool down quite a lot, probably down to slightly below zero, but that's still a lot, lot warmer than the sky. So the roof is still radiating some heat down onto the ground, inside the carport, so that keeps it slightly warmer than everything else. Because of this, all of the moisture tends to condense everywhere else rather than inside the carport. So, even if, by the end of the night, it did get down to below zero, all the water vapour is already condensed everywhere else. So, there's no frost inside the carport.