# Cold Tire Pressure vs Hot: PSI Chart For Extreme Weather

One of my biggest beginner mistakes is to regard tire pressure as stable and unchanged, regardless of external temperature. Teeth-gritting trips through the coldest Texas nights have changed my mind completely since then.

To help novices sidestep my previous mistakes, I will delve into cold tire pressure vs warm differences in as much detail as possible. Keep scrolling for more of my tips.

## Cold PSI vs Hot PSI: How Temperature Affects Tire Inflation

According to basic Physics laws, the volume and pressure of closed-system gas can only stay consistent if the outdoor temperatures remain unchanged. That’s an important reminder for us drivers – since every car tire is filled to the brim with such gas types.

For instance, when I check the tire pressure on my Jeep on a 90°F summer day, the gauge reads 38 PSI, but that number drops to 32 PSI on a 30°F winter morning (both cases with fully infrared tires).

The other way also applies: your tires will experience a pressure increase in hot weather, especially after the engine has finished warming up.

Since cold and hot weather clearly has different and opposite impacts on the tires, it’s important to note the recommended PSI for each scenario.

Since cold and hot weather clearly has different and opposite impacts on the tires, it’s important to note the recommended PSI for each scenario.

For cold weather, it would be best to keep the pressure within the same territories of 32 PSI to 35 PSI

Though some of my friends did mention driving just fine at 30 PSI or even below, such numbers are still pretty risky for smaller and more outdated models (like this 10-year-old Jeep of mine).

So sticking to the golden 32-35 area will ensure you will never encounter accidents on the road.

Regarding hot climates, the optimal pressure rises slightly above the usual range (36 PSI to 41 PSI) as the compressed air takes over more volume. Anything over 41 PSI means overinflating issues are at play; be cautious.

To gain a more concise and comprehensive view of the pressure fluctuations, please have a look at this quick compilation chart:

*Assuming atmospheric pressure is 14.696 or 101.3 kPa

## Should You Check and Inflate Your Tires in Hot Weather?

Absolutely not. As mentioned above, external temperature and tire pressure have a correlated relationship, which explains why you should tread with more caution than ever regarding tire checking!

The increasing temperature – aided by excessive road friction – only heats up the tires at a neck-breaking speed. As the air molecules get hotter, they expand and increase the distances between each other, boosting compression and further inflating the tire pressure.

Due to such expansion, whatever gauge or pressure sensor you use will likely produce inaccurate readings.

But what if you live in regions with all-year-round sunlight and almost no winters (like one of my cousins, who complains he never knows when is the best time to check his tires)?

No worries; some manufacturers do provide specific temperature inspection guidelines for such situations. Remember to scan them carefully.

## Should You Check and Inflate Your Tires In Cold Weather?

Yes. Tire pressure in the cold hasn’t had enough heat to expand yet; your gauge’s readings will likely be much more accurate, guaranteeing no overinflation issues can take over. That’s why I have made it one of my habits to check my Jeep in early cold mornings.

Plus, most manufacturers’ PSI recommendations (the 32 PSI to 35 PSI range mentioned above) are issued based on cold tires – all the more reason to inspect their conditions in chillier climates.

Compared to cold tires, hot tires are more of a wild and unpredictable ride: you might either go right or go horribly wrong with them!

## How Often Should You Check Tire Pressure? Basic Steps to Check Pressure

Many unpredictable variables are at play when it comes to tire pressure; leaving it untreated for too long might put both you and your car at severe risk. I always remind myself to check it every month.

The basic steps:

• Step 1. Check the recommended PSI in your car’s manual.
• Step 2. Use a tire pressure gauge to read the pressure level: put the gauge on your valve stem, then press hard. Accurate readings should show up on the indicator.
• Step 3. Fix the air pressure according to the tire manufacturer’s instructions.

## What Happens If You Drive With Overinflated or Underinflated Tires?

The tires will either expand to the point of blowouts (overinflated tires) or increase friction and lead to premature wear (underinflation).

Either case is a nightmare, especially for old cars like my 10-year-old Jeep. There are no shortcuts; simply avoid both situations at all costs to protect your fuel economy and road safety.

## FAQs

### Is 40 PSI Good Tire Pressure?

Though great for larger cars or vans, 40 PSI might be too much for small cars with 35-PSI limits.

### What Is The 4 PSI Rule?

According to the 4 PSI rule, a correctly-inflated tire has its hot measurements (the pressure measured while hot) rise 4 PSI higher than its cold inflation pressures (the pressure measured while cold).

## Conclusion

For those who still ponder about their tire pressure, I hope my experience sharing has helped lift some confusion. If more clarifications are needed for certain points in my article, remember I’m always available for more questions on proper tire inflation.

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Robert Herrera

President & Automotive Expert at COR Wheels

Robert Herrera has been with COR Wheels for 17 years and has a great passion for the automotive industry. During his time at COR Wheels, he has driven and test-driven a variety of vehicles.

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