I don't plan to ride much in the rain but unfortunately I think it is inevitable that one day I will be caught in an unpredicted rain storm. I asked an avid commuter on Youtube about what to wear in the rain but then it also occurred to me that rain might cause damage to my bike as well.

So my question is this, is there any maintenance that I should perform on my bike after a rain storm that would prevent rust or other damage? Like oil the chain or dry off the water? Or am I wrong. Maybe bikes are made for rain and nothing is needed?

I have one aluminum bike and one steel framed bike. The aluminum bike has disk brakes. Both have derailleurs.