My safe has always been in an unheated garage where temps have ranged from below freezing to upper nineties. Never had any problems at all. None. I do use a Golden Rod and check it periodically to make sure it is still working properly. This has been my experience for 25 years and in different climates, some dry, some pretty humid. As long as the firearm has been cleaned/wiped down properly before hand I would expect no issues.