I love Calmcoat. It's the best stuff on earth. It's oil based and soaks into the skin, so it should be fine in the cold. A friend of mine dealt with a BAD case of rain rot with her gelding this past summer. Her trainer had her trying all kinds of junk, but nothing worked. I gave her some of my Calmcoat and within a week, his skin was all cleared up and the hair was growing back.