Landings, rolls, and the just doing. Alot of people underestimate how much one can improve if they just randomly burst into parkour. For instance if you go to a grocerie(SP?) store, and there is two spaced parking stumps(i don't know what there called, the yellow things that keep your wheels from going to far foward). Just precision them a couple of times. Even if it was cold, this wouldn't be a giant deal, only extending the time your outside by a minute. And then maybe just vault a random rail. Its these little things that can keep you sharp, or even help you progress during the winter.
