The evolved Weather Shirt is engineered for insulating protection from the elements without adding bulk or weight. Ideal for cold-weather training. Weather-defying details The Weather Shirt is engineered for performance and comfort in cold conditions. While technical fabrics handle the temperature, the thumbhole cuffs help keep your hands warm and your sleeves where they should be. There's no rolling them up to check your pace either – the watch window puts your smartwatch stats on show while keeping the chill out. Reflective details add visibility after dark. Warmth, not weight The blend of polyester and lyocell makes our next-gen Weather Shirt warm, soft and light, delivering the performance of its predecessor with even less weight. The channel construction of the fabric traps air that is then warmed by the body to insulate against the cold. At the same time, moisture-wicking properties keep you warm and dry. Clever beats cold We made the Weather Shirt to take the guesswork out of cold-weather training. It’s the top you reach for as soon as there’s a chill in the air. Clever fabrics provide warmth as you get moving and then keep you dry and comfortable as you pick up the pace. So when the temperature drops, your performance doesn’t have to.