I know that there has been plenty of talk on this, but I thought this experiment deserved its own thread.
A HeadSmart Lab study using brand new official NFL Footballs...
All footballs are inflated to 12.5 PSI at 75 degrees...like they would be in a locker room...the balls are then put in a 50 degree room and made wet (there was heavy rain in the AFC Title game and about 45 degrees by halftime of the game).
#1 Colder air will condense the air and decrease PSI in a ball
#2 Wet leather will expand and therefore decrease the PSI in a leather football.
The footballs lost PSI of up to 1.95 PSI --- perfectly in line with what the Patriot balls were. Keep in mind, only 1 Patriot ball was down 2 PSI. The rest lost less than that.
Edit: I failed to embed and have kids to put to bed so here is the link to a video.