I do grill all winter long and I do keep my grills undercover and have had no problems related to moisture. -20 to -30C is pretty cold and I might not want to be out on the deck myself in that range. I did buy a small KK for the sole purpose of a faster heat up durning the winter, bought the 16.5 inch and have had no problems but your grilling space is limited and the grates are closer to the fire which you have to keep in mind. I am very happy with it and it is also easier for me to roll out than the 21 inch high top KK. In the winter, if it is really cold, I usually position the KK just in font of the sliding glass door so I can see the temp from in the house and actually tend to the food on the the grate without even putting my winter jacket on and stepping outside.