In the Ready Mix, Patagonia uses a material that's inherently very water-resistanta fine-weave polyestervarying the thickness of it in areas most likely to get wet (shoulders, for instance), then coats it all with its proprietary Deluge finish, which repels water like rain off a goose. So, in short, it's just the ticket for what you want to do.
The beauty of a piece such as the Ready Mix is that you can just toss it over a super-light layer, such as Patagonia's Capilene Silkweight Crew ($34), and get some comfortable rain protection when it's not real cold. Much as I like pieces such as the One Jacket, they're best suited for cool-to-cold conditions, especially for aerobic activities. I mean, a One and a light synthetic tee and you can mountain-bike in the snow (I know, because I have).
Get the scoop on other soft-shell options in Outside's Gear Blog .