I'm definitely playing the odds when I bring a poncho/tarp. The weather moves so quickly in CO, especially the higher you go, that I'm rarely caught in an all-day storm, but it can happen.

I usually bring an old SD rain jacket that only weighs about 4oz. It's not the most rain-resistant, though, and is really somewhere between a rain and wind shell. It will hold off rain for a few minutes --long enough to fill in a cathole.

I'd like to try a poncho and wind shell combo (thus my thread asking if anyone had done that and used DWR spray effectively) but I know I'd be playing longer odds, that way.