Spantex deck coating made by Tex Enterprises in Auburn, WA is a good product in any climate. Spantex is made out of Hypalon rubber and has held up very well in Alaska. I have talked to a guy who has had it on a flat garage roof that is used as a deck for about 26 years. It is applied over untreated wood. It also works on other surfaces. Their website is www.Spantex-usa.com.