Great design for high-output activities - Smartwool PhD Ultra Light Sport Jacket - Men's

I have been searching for a wind shell that dumps heat and moisture effectively on my cold, windy, 15-mile winter cycling commute. Even the lightest shells trap moisture and leave your underlayers damp during hard exercise, unless you're willing to take them on and off periodically. On a bike this isn't practical, and unzipping the shell doesn't help with areas like your arms. I've tried Gore-Tex shells, convertible shells (zip off sleeves), layering wind vests under shells, but I always end up soggy and cold by the end of the ride.

I thought this Smartwool jacket was just another shell lined with ultralight wool, but its design is more thoughtful and well-executed than any minimalist shell I've seen before. It's mostly ultra-thin nylon but has panels of Smartwool fabric replacing the nylon completely in areas where sweat accumulates, under the arms and a panel down the center of the back. In addition to its moisture-venting properties, the wool is also stretchy, allowing the jacket to stay snug against your base layer. There are strategic vents along the top of the shoulders, and the collar is lined with a thin layer of wool. The nylon is extremely thin and as noted the jacket stuffs down into a fist-sized ball in it's reversible chest pocket. Like all super-lightweight jackets treat it carefully.A mens medium was true to size and close-fitting, with room for only a couple of thin layers underneath.

The DWR coating worked to keep a light drizzle from soaking the nylon, but this is not foul-weather gear. It is completely wind-proof however, and kept me warm in temps from 25-40 F with just a wool baselayer underneath. My only criticism is the tiny zipper and the lack of a longer back panel (it's not a cycling-specific jacket, but I wish they would make one).