Weather Tidbits: Air Temperature vs Tire Pressure

This Weather Tidbits will discuss about the relationship between air temperature and tire pressure. You may have noticed on a cold winter morning that the tire pressure on your car may be a bit lower than the past couple of days prior. This is especially true of the cold air invasion is sudden. Tire pressure lowering in cold weather can be explained by the ideal gas law.

The ideal gas law equation is PV=nRT where P=pressure, V=volume, n=amount of substance, R=ideal gas constant, and T=temperature.

We can isolate P by dividing V on both sides to get P=[(nRT)/V]. Given that temperature and volume have a direct relationship (i.e. as temperature decreases, volume decreases), we can say based off this equation that as air temperature decreases, and thus the volume of air decreases, the tire pressure will decrease as well.

The recommended tire pressure stated in the owners manual doesn’t necessarily change during cold weather. But you will likely be checking you tire pressure more regularly in winter than summer.