Up here that is called the average temp!!!
I tend to do most of my ice fishing at -25 and warmer, although I have been out there when it's 10 or 15 degrees colder. Just not as much fun. At -25 the hut door stays open with the heater on 1/2. When it gets colder than that the door closes and the heater gets put on full. I just don't like the lack of air movement to get the CO out of the hut when it's sealed up, even with the door cracked, windows cracked and vent open I still get hedaches due to the CO in the hut. May have something to do with the 14,000 btu heater though.
My first couple of years up here I would just turn my back to the wind and fish in -25 to -30 but the hut and heater deal is much more comfy.
Oh yeah, current temp is -31 with little to no wind.