Winter riding can have its fair share of challenges, most of which can be addressed by the right combination of clothing and gear. However, we'd argue that trying to regulate body temperature while climbing is probably one of the most difficult parts of winter riding. After you sweat under your jacket during a long, exhausting ascent, the windy summit can quickly cool your body off, making the fast descent all chattering teeth and tense shoulders. Castelli took on the challenge of creating a jacket specifically made for winter climbing last year with the inaugural version of the Alpha. The brand received such positive feedback for the effort that the jacket is back, now available as the Alpha Jacket for women. Castelli uses the typical sandwich of a Windstopper 150 membrane and thermal insulation in the Alpha, but the decision to keep the layers detached is what separates it from more traditional winter jackets and allows for the temperature control needed while climbing. As you heat up, unzipping the shell to let in the wind exposes the jacket's thermal layer, not your base layer or bare chest. The thermal layer insulates while remaining permeable, letting the air in evenly rather than in a shocking blast of cold, and it's able to wick moisture away continuously as you sweat to keep you as dry as possible when you reach the summit. At the top, you'll be able to zip back up as you take in the view without feeling clammy and cold for the rest of your ride. As you begin that descent, you'll feel the benefits of the Gore's lightest Windstopper fabric, Windstopper 150. Though it's used as the shell of the Alpha, it's actually a windproof three layer, four way stretch knit fabric with a water resistant DWR coating, so it doesn't feel overly bulky. It fits just as well on a base mile ride as it does while you're riding at tempo or climbing out of the saddle, and the ventilating back panels mean that it doesn't trap heat. Overall, expect the Alpha to have an aggress...