Why your tire pressure light comes on when it gets cold

The first cold morning of fall, half of Hamilton sees the same orange light on the dash. Here is why.

Cold air takes up less space

Tire pressure drops roughly 1 PSI for every 5 to 6°C the temperature falls. A tire set on a warm afternoon can be several PSI low by the next frosty morning.

Where to find the right number

Look at the sticker inside the driver's door jamb. The number printed on the tire itself is the maximum pressure, not the target.

Check it cold

Measure before you drive, or after the car has sat for a few hours. Driving warms the tires and gives you a false high reading.

When the light stays on

If the light stays on after you top up, a sensor may be failing or a tire may have a slow leak. We diagnose TPMS sensors and repair slow leaks. Call (905) 586-2626.