How often should the tire pressure be checked?
Tires can lose 1 psi per month under normal conditions. Tires also can lose 1 psi for every 10°F temperature drop.
Check tire pressure at least once a month and before going on a long trip. Also, don't forget to check the spare tire to ensure that it's properly inflated and ready if needed.
Air pressure should be checked when tires are cold. Inflation pressure can increase several pounds during a long trip in hot weather.
When checking and measuring tire pressure, also inspect tires for uneven tread wear, cracks, foreign objects, or other signs of wear or damage. All tire valves should have valve caps.
Check and measure the air pressure with your own gauge. Some air pressure towers at service stations are inaccurate because of exposure and abuse. Also, do not check pressure by just looking at the tire. A tire can be under inflated by 10 pounds and not appear to be low.