Ah, easy for me. Rain pants (the kind that go over regular pants), and a jacket that is waterproof or will dry easily. To water proof my stuff, I put a trash bag in my bag like you would a trash can. Have the sides hanging over. Put your stuff in like usual, and then put the bag over it (no tying involved). When you're at you destination roll the bag half way down, so you won't have to repeat the process if you're going out again.