For me, the days Ive done the best are clear windy cold fronts! I can think of my best hunts and 20-30 mph winds at -10 below or colder where the best days I've had. Now, they made for the best hunt, but decoys had so much ice build up on them they were double in size. Hands and face were numb.
The coldest day about 8 Thanksgivings ago, it was a little above 0 when we were putting up decoys. When the sun came up, the wind came with it. We were in heavy gusts, clear blue skies, and a wind chill that hit -30 at its very worst. We were cold and froze out the water pump on the motor. We were a mile and a half from the landing with ice forming between there and the blind. By noon we had a four man limit of ducks and geese, but a dead motor, ice, and a mile and a half of water to cover. Couldn't row because of the ice, so we ended up having to walk the shore pushing the boat ahead of us to break the inch of ice that formed throughout the morning. We got back after dark, all of us missing our Thanksgiving dinners. That was the worst-best day of hunting I ever had!