Tom, I live in Cali (SF area)where it's pretty mild. I use a canvas cover, a silver tarp and 3 drizairs and have no problem. You may want to add a couple more? Wash is typically wetter than Cali, right? I had thought of the ceramic heaters, but I did not feel comfortable leaving an electrical appliance in a covered boat with all those gas fumes. (Bomb!)This summer my boat gets to move into her new garage!!