It is not recommended to cover your RV in the winter months stored outside. Using tarp's to cover it may keep water and snow off, but moisture will still get underneath. Worse, moisture under the tarp will be trapped, unable to evaporate. The result is mold or mildew. If you do cover the unit, use something that is breathable when winterizing your RV.

One way to control moisture inside the RV when stored is to place something inside that will absorb the moisture like a chemical absorbent. Most come in a plastic container, and you simply open it and set it inside the camper. It will work similar to silica gel, and absorb the moisture from the air. The plastic container keeps any moisture from draining onto the floor, or the product from causing any stains. Most moisture removers are made from Calcium Chloride, the same stuff you melt ice off from a sidewalk with.