I wouldn't go without mine in wet weather. The rain falling down isn't much of an annoyance as it's relatively clean. It's the rain that falls up from the road that you need to deal with, which will also continue long after the rain has stopped. It's quite amusing to ride straight through a puddle and see a torrent of water falling from my front fender instead of showering me in the face. If you're gram-counting, without them you'll probably swallow their weight in muddy water anyway.