Well if it starts raining and it gets too bad, coulden't we just stick to a mall or something and be annoying there? I mean, I know it isn't what exactly what we'd want to do for someone's birthday, but.. It seems like a solution if it doesn't stop.(Though when it comes to Oregon, you can't expect what the rain would do. It might not even do that XP)
As for umbrellas.. XD I'll have to hide under one with someone if needed. I have none at my house. The last one we had broke because I used it in a rain storm on the way to school a few years back.. o.<