As per the Tire and Rim Association (TRA), it is recommended to measure the cold inflation pressure of tires when they are at the current atmospheric temperature, without factoring in any pressure buildup caused by vehicle usage. This means that tires should be checked when they are cold, such as after the vehicle has been stationary for at least three hours or driven for a distance of less than one mile. The most convenient time to check the tire pressure is in the morning, following an overnight parking period.