Detectors of today should be able to handle the humidity anywhere. That is not to imply that one should leave a detector outside over night, as an example, but humidity shouldn't be a problem under normal circumstances, I would think, anyway. I, too, keep my detectors inside when not in use. The only time they stay in my vehicle over night is when I'm traveling. When I am not traveling with them, though, I never leave them inside a carry case. Over time, a carry case can attract moisture. HH jim tn