Why Your Tire Pressure Changes With the Weather - And What to Do

If you’ve noticed your tire pressure warning light coming on more often during the winter or early spring, you’re not imagining things. In Canada, with our extreme temperature swings, it’s completely normal for tire pressure to fluctuate — and understanding why can help you stay safe on the road.

​​Why Tire Pressure Changes
Tire pressure is directly affected by temperature. Air contracts when it’s cold and expands when it’s warm.

• Cold Weather: For every 10°C (18°F) drop in temperature, tire pressure decreases by roughly 1–2 PSI. This means tires that were perfectly inflated in the morning can feel “soft” by evening on a cold day.
• Warm Weather: Conversely, for every 10°C increase, tire pressure rises about 1–2 PSI, which can cause tires to feel firmer than usual.

In Canada, where temperatures can swing drastically from day to night, this means tire pressure naturally fluctuates with the seasons.

What You Should Do
1. Check Your Tire Pressure Regularly:

• At least once a month, and whenever there’s a significant temperature change.
• Always measure tires when they are cold, meaning the car hasn’t been driven for a few hours.

2. Inflate to the Recommended Pressure:

• Find the correct pressure on your driver’s side door jamb or in your owner’s manual.
• Do not rely on the number printed on the tire itself — that’s the maximum pressure, not the recommended operating pressure.

3. Look for Warning Signs:

• Tire pressure warning lights on your dashboard.
• Tires looking visibly low or feeling soft while driving.
• Uneven tire wear (e.g., worn edges from underinflation).

4. Consider Seasonal Adjustments:

• In spring, check after cold nights or sudden warm days.
• In winter, check more often because cold temperatures can reduce tire pressure enough to affect handling and braking.

Why It Matters
Incorrect tire pressure can impact:

• Handling & safety: Soft tires reduce traction, while overinflated tires can make your ride harsher and decrease grip.
• Fuel efficiency: Underinflated tires increase rolling resistance and waste gas.
• Tire longevity: Both under- and overinflation lead to uneven wear and shorten tire life.