The Denver Broncos have been a favorite in every game they have played this season. Up to this point, nothing has changed.
The line reflects that the oddsmakers believe more in Peyton Manning and the Denver offense than Richard Sherman and the Seattle defense. It's easy to understand why, considering the Broncos set numerous offensive records with their play this season. However, no quarterback that has led the league in passing yardage has ever won the Super Bowl that season.
Currently, the weather in East Rutherford, NJ on Sunday doesn't appear to be much of a factor. The forecast is sunny with a high of 37 degrees and a low of 24 with very little wind, per The Weather Channel.