Our Comcast digital signal didn't like the freezing weather either. I couldn't sleep Wednesday night and got up to watch television. The picture was tiling so badly that I finally called and made an appointment for a tech to come see it/ fix it, in the afternoon.
Nearly 3 a.m., when I went to sleep, it was still acting up. When I woke up, it was fine so I canceled the visit from the tech. As the afternoon chilled, occasional tiling flirted with the picture again. The sound tended to come and go, briefly.
Today it is warmer and the pix and sound are fine again. Like ourselves, Comcast is a hothouse flower . . .