[Len J]

Originally Posted by velomonkey

"The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas's absolute temperature."

So P/T = Constant

For comparing the same substance under two different sets of conditions, the law can be written as:

P1/T1 = P2/T2

I'm also going to do this in Metric to avoid other potential errors. And I apologize that I am 20 years from doing this sort of work

12.5psi = 86.18kPa ( kilo Pascals)
75F=23.89C = 297.04K
30F=-1.11C = 272.04K

So
86.18/297.04 = P2/272.04

0.29= P2/272.04

P2=78.93kPa

78.93kPa= 11.45PSI

Temperature change from 75 to 30 degrees would result in the balls losing 1 pound of pressure per square inch.

Why don't you all complain that the Pats did a rain dance prior to the game.

But it was 51 degrees at game time not 30.

Len