Warning, Tire Pressure Low, Add Air!

March 12, 2019 // Article by: Thomas M. Else

Have you ever wondered why your tire pressure fluctuates with the change of temperature and seasons? 

Before we get into the explanation of why this happens, let’s take a look at what normally happens with your vehicle’s tires on a daily basis. When you first start your vehicle in the morning, your tires are cold and the Tire Pressure Monitoring System (TPMS) will give you a true indication of your actual tire pressure. Always check your vehicle’s manual to see if your tires are properly inflated.

As you drive your vehicle the temperature of each tire gradually increases due to friction, which in turn causes the air pressure inside the tires to rise. Eventually, your tire pressure will stop rising and level off. Just from driving alone, your tire pressure will go up by several pounds per square inch (psi). This whole process will repeat itself the very next day.  However, as we progress into winter, daily temperatures will continue to decrease, which in turn, will cause your tire pressure to drop. 

According to Good Year Tire, for every 10-degree Fahrenheit drop in air temperature, tire pressure will lower by about 1 to 2 PSI. The reason this happens is the temperature of a gas is directly proportional to its pressure. In other words, if the temperature of the gas decreases, the pressure decreases. Similarly, if the temperature of the gas increases, the pressure increases. So, the next time you start your vehicle and the temperature has noticeably dropped from 24 hours ago, your tire temperature will be colder and hence its pressure will be a few PSI lower. This definitely does not mean you have a slow leak; it is just a normal response to the decrease in air temperature. Safe driving and keep your tires properly inflated!