If you're lucky enough to live somewhere that winter conditions stay a bit above freezing, chances are most winter-ready cycling jackets are too overbuilt for your base mile and training rides. For the rest of us, there are the transition seasons, when summer's heat has long gone, but gusts of ice are still a ways away, and we need the perfect jacket for that in-between. Whether it's for all-winter, or just the shoulder-seasons, Castelli's Transition Jacket is ideal for the days when its not so cold outside that you need to don all of your winter layers, but just to take the chill away. The Transition Jacket is built to be Castelli's lightest jacket for fall, and light winter riding. It's crafted using GORE-TEX Infinium X-Mid fabric for the front and sleeves, which excels at wind protection, and breathability, so you can hammer out the miles and let your heart rate rise without being worried about getting bogged down with perspiration. In back Castelli employs its own Warmer fleece fabric that offers a soft, brushed feel, plus a little extra breathability to allow sweat to escape when you're putting down big efforts. The front is finished off with an asymmetrical YKK Vislon zipper that keeps irritating zipper ends away from your chin when a gust blows by and you need to tuck in, and the back is topped off with three deep pockets to stash your essentials for the mid-ride coffee break. Lastly, for an added hit of visibility, Castelli includes a reflective stripe down the back to help you stay seen if the day turns grey and dreary. According to Castelli, the Transition jacket works best in temperatures from 46 - to - 60-degrees Fahrenheit, but your comfort will ultimately depend on how hard you're riding, and how you choose to layer.