We were in Albuquerque in 2010 when a front came through dropping temps below zero, even during the day. We were in a Beaver Motorhome at the time with diesel heat, dual pane windows and decent insulation. We did not freeze but did get cold. The next day a friend and I went through the park to make sure folks were OK. Some of the trailers froze, went right through the walls into the pipes despite electric heaters and furnace working overtime. Everyone survived it but it was telling about the abilities of RV's in cold weather. Choose your rig wisely