Why does my tire pressure light come on when it gets cold?

Your tire pressure light comes on in cold weather because cold air contracts, which lowers the air pressure inside your tires.

Why it happens:

• When the temperature drops, tire pressure usually drops too. A common rule of thumb is about 1 PSI for every 10°F decrease, though the exact change can vary.
• Many TPMS systems turn on when a tire is significantly below the recommended cold inflation pressure, often around 20% to 25% low depending on the vehicle.
• A sudden cold snap overnight can drop tire pressure enough to trigger the warning light by morning.

Why it may go off later:

• As you drive, the tires warm up and the air inside expands, so the pressure can rise enough that the light turns off. But that doesn’t necessarily mean the tire is properly inflated when cold.

What to do:

1. Check the pressure when the tires are cold — ideally before driving, or after the car has been parked for at least a few hours.
2. Use the door-jamb sticker for the recommended PSI, not the maximum PSI on the tire sidewall.
3. Inflate the tires to the recommended cold pressure. If the light stays on after that, you may have a slow leak or a TPMS issue.