Tony.. I know you use a cover but for those of you who don't.. If you are not cooking, it's really best to keep them covered. The cold or snow is not an issue but the repetitive freeze thaw cycles and if one does not maintain the integrity of the acrylic waterproof jacket, water getting into the insulation and freezing can be a problem. You will know if your acrylic jacket is leaking because it will blow steam vapor when taken over 550ºf..