[B_and_D]

I know that our climate is vastly different from yours (Central Coast of CA - it's 68 degrees outside as I type and we've been having a heat wave). We keep our TM open all year and have one of the breathable covers. I wish that we'd bought it right away. The winter before last it was so wet with the TM uncovered that it did start to get a bit of a mildew smell. We used to go out there every night and watch TV, so we noticed it right away. We opened it up and ran a fan, washed the curtains, all the sleeping bags, and the pillows. Last winter, it stayed nice and dry inside and CLEAN on both the inside and outside. It was such a pleasure to just take the cover off and have it ready to go, clean, and the tail lights nice and dry & not corroded. We used to have to clean out the tail lights before leaving, they were always damp and had green stuff growing inside! I tried putting plastic bags over them but it didn't help.

Since I have no experience with your climate, I'd suggest that you try it and then inspect the TM every week or so to make sure that it stays mildew-free.