So there's a little bit of misinformation on this thread, wind chill does not effect water freezing. (Just looked it up because I thought I had read at one time that wind chill only effects humans and animals.) Now for the question, We have left from Nebraska twice in Feb and once in Dec, winterized the camper in the fall, day or two before leaving, unwinterized, turned the furnace on about 50, our camper is polar ready, has heat ducts that blow on fresh tank and holding tanks, camper dealer told me that it would take multiple days at 20 degrees to freeze water lines in camper with no heat. Put about 2/3 tank of fresh water in case where we stop it's going to be cold and fresh water hose would freeze. Only time we had anything freeze was 2013 and camped at Stanford, Florida, lol, temp was 32 when we went to bed and 32 when we got up, froze up in the brass elbow coming into the camper, unhooked, left in sun for 1 hour and was fine. The brass conducted the cold better. We don't leave anything that will freeze in our pantry because they are not heated. Like Teamubr, we camped one time on the way home in Missouri, they had just had a huge snow storm go through, (think 10"+) the campground pushed out the sites, pulled on the snow and camped for the night, nothing froze, didn't hook up to water of course, and couldn't find the sewer connection.