Zach’s Weather Whys: Why does my tire pressure drop when it gets colder?

Zach's Weather Whys

PEORIA, Ill. — It’s getting colder in Central Illinois as we step toward December.

With a lot of holiday travel in the forecast, we’re talking tires this week. You’ve probably noticed the low tire pressure light come on after a big cold snap.

No need to panic, there’s a good reason for that. Your tire pressure drops and increases based on the outside temperature. Let’s start with how it works on a cold day. The pressure inside a tire can drop about one pound per square inch for every ten degrees drop in temp.

Look at it like this: it’s full of air molecules that are constantly moving. When a strong cold front plows through – the temperature in the tire also cools and molecules slow down as a result.

Molecules move slower in the cold and the space inside the tire decreases. Sure there are fluctuations in temperature during any given day, but it takes a big drop for your tires to notice.

You can easily fix this issue by just adding air to your tires. The right amount of air varies by the manufacturer of tires.

On a side note, a hot summer day will actually cause a slight rise in tire pressure – but that’s not as serious.

Yes, I’m daydreaming of summer – but anyway it’s best to adjust tire pressure if needed.

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