As someone else has already said, Series 1 and 0 are fine in rain. I've gone for little dips in the lake with my Series 0 watch, and dunked it into a bucket of water while washing dishes, and it's perfectly fine. Many people, including Tim Cook, have said they shower with the Series 0 watch. The Series 2 watch is even more water resistant (technically, there is no such thing as water proof, just varying degrees of water resistant), but Series 0 and 1 were pretty water resistant to begin with.
Yeah you're, but in my opinion, people who does these kind of things, when the company says explicitly, don't do that, are so brave, even though people like Tim Cook says he does... Call me chicken