Takeaways:
* Passing completion drops by about 2% during games played in extreme cold.
* Punts made in extreme cold average 3 yards shorter than normal.
* The air pressure of a football is reduced by 20% in extreme cold.
* NFL games average a 1.79% fumble rate. During games played in extreme cold, that rate increases to 2.42%, a 35% increase.
Extreme cold can have a marked effect on the two essential components of any NFL game: the players and the football.
While the cold may not stop a player from executing an effective play, it certainly makes their jobs more difficult. Cold external temperatures force the body to send less blood to the extremities in order to maintain a healthy core temperature.
In as little as 15 minutes, a player¡¯s grip strength can be cut in half. Not an ideal situation for a quarterback trying to throw a perfect spiral.
The cold air irritates a player¡¯s respiratory system, making it harder for them to catch their breath, and stiffens the muscles so they can¡¯t stretch as well.
These reduced temperatures also cause the body to burn glucose five times faster than normal, meaning there isn¡¯t as much energy left for powerful plays on the field. Reaction times can drop by 45% in these conditions.
Not only does the cold affect a player, but it also has some influence on the actual football. In extreme cold the air contracts and becomes more dense.
NFL regulations state that all game balls must have a pressure of 12.5-13.5 pounds per square inch (PSI). When temperatures change by a factor of 10?, pressure changes by a factor of 1 PSI.
This means that an inflated football can actually lose pressure and become slightly smaller and under-inflated when the weather gets colder. Within an hour, a football¡¯s air pressure can be reduced by 20%.
Cold, under-inflated balls also have a lower coefficient of restitution. In other words, the ball becomes less bouncy and will come off a kicker¡¯s foot slower than normal temperatures.