I split my time between Oregon where the winter is a steady drizzle and in Montana where summer thunderstorms unleash all hell. I haven't had this in a t-storm yet, but its kept out the Oregon rain just fine. It weighs in just as light as an Arc'teryx, costs less than half as much, and in my opinion is made just as well, plus you've got Patagonia's environmental cred. I've taken it on a number of medium intensity bike rides in the 50s and it breaths excellently. However, I took it up to Hood and was a little disappointed with its ability to break wind, not as good as previous shells I've had. The cut is good, I'm 5'9" 155 and a medium fits perfect, loose enough to layer under, but slim enough to look good. The only thing that bugs me is that unless its really cinched down the hood doesn't keep any rain off your forehead.