You don't change the date of the Superbowl; you play the Superbowl--and any other football game--no matter what the weather. I do get that if there's lightning that you might suspend play. But you don't cancel on account of cold. Otherwise, why would you play the game in an outdoor stadium north of the Mason-Dixon line?
This is a case where the NFL needs to lie in the bed it made. Caving into the pressure from business interests to play the game in the New York area was a mistake. Changing the date will throw off the plans that people make to enjoy the game.
Let us hope that someone has the common sense to go forward no matter what and play the damned game.