Recommended automobile tire pressure is affected by ambient temperature and atmospheric pressure. Depending on whether temperatures and atmospheric pressure fluctuate up or down, tire pressure can change accordingly.
Air temperature changes can cause tires to lose a significant amount of air pressure. Because tires are permeable, air can escape through pores in the material, particularly during warm weather when the material tends to expand more.
Atmospheric pressure decreases as altitude increases. Conversely, atmospheric pressure increases as altitude decreases. Therefore, changes in elevation affect recommended tire pressures as the vehicle moves through different altitudes.
Regardless of the cause, it is important to maintain proper tire inflation levels and check the pressure at a minimum of once per month.