When a runner reaches for their jacket, it's for good reason. Unlike cycling, the relatively constant, slower pace of running means that a windbreaker is only necessary when there's a really icy wind outside. Water-repellent or even waterproof running jackets make it possible to continue running even in the most adverse conditions. In darker months, the increased visibility offered by a jacket with reflectors is another good reason to wear one. For the summer, you'll find extremely light and breathable running jackets which are wind and water-repellent. Whereas, for colder seasons with rain and snow, there are versatile designs with element-proof outer material and mesh inserts or vents for improved breathability and effective moisture management.