I live in Maine so winters are cold. I use the black rubber Fortex bowls and fill them up once a day on work days and twice a day on my 2 days off. The rubber bowls are easy to stomp the ice out of most of the time, though a couple of times I had to bring them inside to thaw. I keep 2 sets of bowls so I can alternate them if I have to bring one inside.
Also, I buy the electrolyte and vitamin powder that I mix with the water. It keeps the water liquid a bit longer than plain water.