...other than "how bad is Chase Utley's hair?"
... "Which division is the true Frostbite Division - the NFC North or the NHL Northeast?"
Let's check the numbers, by average low temperature.
Green Bay 35°F
Minneapolis-St Paul 36°F
Winner: the NFC North. Extra points for having two of those teams playing outdoors, too.
But, it's not all about temperature, especially since these all include the summer months. We could look at wind chill, but let's see a pure measure of winter. Average annual snowfall:
Green Bay 48in
Minneapolis-St Paul 50in
The winner, in an avalanche: NHL Northeast, with three cities averaging 7 or more feet of snow every year. Now that's where you should be playing winter sports.
One last note: Although its snowfall is a pedestrian 44 inches, Winnipeg's average low temperature is 26°F. The average low temperature in Phoenix is 61°F. BRING BACK THE JETS.