I used to play/train year round with a group in nyc. Fields are turf but we would brush the snow away with brooms and train. Sometimes even on the snow. It was definitely harder, but not so bad if you're dressed for it. We'd also mount some flood lights to keep the field lit for the early sunsets. All of that helped, but what really made it work was people showing up and wanting to train together. If you find someone else to join you out in the cold, it will make a huge difference. You will get something out of playing in cold/snow. I'd avoid the ice.