OP
Here in the mid-Atlantic, with our temperate climate, we go through freeze-thaw cycles all winter, with temps that can easily go from the low-20s to the mid-40s from one day to the next. Summers are typically hot and humid.
For about 30 years, I have had the same large Liberty safe in my unheated garage, protected by two Goldenrods, and have never had an issue with rust or corrosion on anything in that safe...guns, magazines, bayonets, etc.
Several years ago, I ran an inadvertent test. I came home from shooting, emptied my range bag, and unintentionally left a single mag for my Ruger Mark II in the bag. I then sat the bag on top of the safe. The other mags were on the top shelf of the safe, inside and less than a foot underneath where the bag was sitting. A couple of months later, when I opened that range bag, the mag I'd left in there showed a veneer of light surface rust, while the mags stored inside the safe were pristine.
