Second that.
Lower temperatures lead to lower pressure and higher temperatures to higher pressure.
Right. But to do the calculation, the temperatures must be in Kelvin, not Fahrenheit or Centigrade. My calculations (which might be wrong, as it's early for me) show that a 72 F to 49 F temp drop would result in a roughly 7% pressure drop.
If the ball was at 12.5 psi originally, this would put the ball's pressure at 11.6 psi at game time.
This calculation assumes that - untouched - the ball's volume remains roughly the same.
...and those are hardly the only variables.
Using those same gas laws, filling the ball immediately before submitting will give much different results than if the balls were filled, then stuck in the hold of a bus, then filled again. Filling a ball warms the air...potentially a lot.
There’s also leather stretching from being wet, and changing the volume.
...and no idea when the measurements on the Colts balls were done - reporters have noted that they are unable to verify that.
I just keep coming back to the Ray Guy episode of Mythbusters where they repeatedly tested footballs filled with air, helium and other gasses. And could find no statistically significant difference in how far they went.
Please convert from psig to psia.