pad locks, have had better long term doings with the ones that are coated in a rubberish substance, and a little plastic cap over the key hole. *lock ends up some what water proof* and more so dust proof.
generally PB blaster, and tapping with a hammer. though normally requires PB blaster when i first find i can not open lock, then waiting a day, and re hit with BP blaster and a couple taps of a hammer to free stuff up. then once free'ed up and removed, messing around locking/unlocking a few times with some additional PB blaster to work everything free and getting it operational again. granted by the time i end up getting lock working again i have made a mess, and hands greasy and no real way to open doors without leaving smudge marks on everything, and paper towels / rags blowing away due to being outside.
brass locks, seem to have better luck with. though with them it is same as winter. and needing ice melt spray. to unfreeze them. even in summer brass locks will still collect dust and crud in them. and may need some PB blaster to start turning/sliding easier.
prefer locks with a key, over combination locks. combination locks have made my fingers raw and have gotten a couple paper cuts from different styles due to rusted / cruded up / frozen up.