Generally speaking, as you will have seen with the items we looked at in our list above, they are designed to be protected against weather damage. This is usually via vinyl coating (or similar plastic) on any cables or exposed metal surfaces. Because of this they are typically low maintenance. One thing you should do is to always ensure the lock is as dry as possible before you put it away if it has gotten rained on.
One exception to this rule is the locking mechanism itself. An occasional spray with a lubricating oil like WD40 will help to keep it working nice and smoothly.