MORE AIR IN YOUR WINTER TYRES Temperature has a significant impact on tire pressurization. For summer tires, we (Nokian) recommend using the vehicle manufacturer’s suggested tire pressure. For winter tires, you should inflate the tires to 3 PSI above the summer tire recommendation, since tire pressure decreases as much as 1 PSI with each 10-degree drop in temperature. The temperature in a warm garage can be up to 60˚F higher than outside. If the tire pressure is measured inside, it will be too low for outside temperatures.