A WARM SWEATSHIRT FOR COLD-WEATHER RUNS. Look outside before your run at dawn. Is that frost on the window? Is the sidewalk glittering with snow? If so, it's time for this adidas running sweatshirt. It slips over your t-shirt to keep you warm when the weather turns chilly. The fabric manages moisture so you don't go from wet to cold and clammy during the course of your run.