Originally Posted by Looigi

Venting helps, but if it's colder in the garage/shed than ambient, condensation will occur. This happens in winter when a warm front comes though after a spell of cold high pressure. Heck sometimes I'll open the garage door in the morning and the vehicles all get covered with condensation, or all the windows will fog up on the outside as I drive off.

Temp cycling with varying humidity is less optimal for storage than constant low humidity conditions.