In Lower Alabama, we leave the vents open and the windows cracked about 1/2 inch. I keep an eye on the weather, since we are one of the wettest places in the US, to determine if the windows need to be closed. The window blinds are down most of the way....leave them up about an inch to allow better air circulation. I make sure the seats are all covered to prevent sun damage. The PC does not stay home much longer than a month at a time, so the wheel covers rarely make it out of the garage.