Baselayers are helpful on the bike year-round, but we can understand eschewing one in the summer months for simplicity's sake. Once the leaves begin to turn and the morning temperatures drop, however, a trustworthy baselayer becomes far more of a necessity. Craft believes that the right first layer is the key to staying active in the cold, and its Women's Short-Sleeve Active Extreme 2. 0 CN Baselayer demonstrates the Swedish company's expertise. The contoured, lightweight top comes constructed with a polyester main body in a channel knit, which establishes a layer of insulating warm air next to the skin when you start pedaling. The fabric continuously pulls moisture away from your skin to ward off clamminess once you warm up, and panels of Coolmax-Air help the cause by further encouraging rapid moisture transfer. These properties make this a baselayer you can wear in a wide range of temperatures, depending on how you layer. It pairs excellently with a thermal jersey or jacket on cold days, and allows you to squeeze another few days in with your favorite summer jersey too.