Last week we had a day that was -38, burr. I have this waterer in my unheated Hen house made by Farm Innovators "All-Season" Heated Plastic Poultry Fountain. I don't know what the temperature inside that coop was, very cold I am sure, the water did not freeze. I was impressed, it advertises to keep water from freezing until 0. I think it out did it self.
Here are a couple images of what "cold" looks like.