This is football! It's meant to be played in crap weather. One of the greatest football championship games of all time was in New York- the Giants and Colts game that went to OT and put the NFL on the map in the 50's where Alan Ameche scored the game winner.
I think this is great! And who knows? It's not like there could'nt have been a monsoon in Miami. It's not like the weather isn't a factor anywhere else that doesn't have a dome. Yes, it could snow and could be bitterly cold and cause the game to be sloppy, but so what? That's just part of it. And the players will deal with it, as will the fans.
Heck, if I was a fan, I would be MUCH more worried about the astronimical ticket prices, as well as the cost of lodging in NYC and the 50 dollar cab ride from the airport to Manhatten than I would the weather.