Another reason for play in winter is strength training. Obviously one wears more clothing out on the course than in summer. That means weight. You are wearing more clothing to weigh your limbs down. So by the end of the snowy winter months, you have gained strength in your throwing arm, as well as other muscles in your body due to trudging through ankle high snow or deeper.
Good article on cold weather gear. For me...I gotta get some mittens...gloves keep my fingers cold. I have not succumed to screws in my shoes just yet.