Gary,
Back in High school I got someone a tennis racquet for Christmas and we went out on Christmas day. There was some ice on the court, so it was like playing on wet grass or something. The ball would basically skid super low when it hit the ground.
When I started coaching the high school team this year the first 2 days of practice it was warm enough to get out to hit, but we had snow flakes starting to fall. But nothing accumulated on the courts and the students said they wanted to keep hitting... I was hitting too, it did not bother me, kinda funny though.