I can't recommend enough those black rubber (Fortex) pans for winter watering. It's puzzling for me to see so many people worrying over frozen water. I live in a cold mountain valley in Vermont but I use the black rubber pans for water and I keep them outdoors in the sun so the water never freezes in the daytime, since typically the coldest days are also the sunniest days. It only freezes overnight, which doesn't matter because they're sleeping anyway, so all I have to do is flip the pan over each morning, stomp on it once to get the ice to fall out, and refill it with a jug of warm water and I'll all set until the next morning. I have a feeling the pan will last longer than I will and I think I paid about $4 for it.