Don't worry about the windchill. It only means the pots will cool down just a bit faster.
At 15F with a winchill of zero, the pot will never go below 15F.
I think the easiest thing to do is put the pots in a closed cooler outside. If you get exceptionally cold nights, bring the whole cooler inside, but don't open it, AT ALL. Return it to outside the next day.
