Why Does Tire Pressure Change?

Many factors affect tire pressure, and that is why it is so important to check your tires at least once a month and before going on long trips. Tire pressure can decrease due to tire damage, slow leaks, changes in outside temperature, and from normal, everyday driving. For example, when the weather changes, your tire pressure changes too. For every drop of 10 degrees Fahrenheit in temperature, your tires lose 1 psi. Tires also deflate naturally over time, as much as 1.5 psi per month.