tire air pressure in winter?

It is true that the colder the temperature, the lower the tire air pressure gets. And, as temperatures warm, they go back up again. It's a good idea to adjust tire air pressures accordingly when the weather changes. If all tires are at 26 now -- put them to the pressure as listed on the tire placard on the driver's door jamb. Make sure you fill tire air pressure when the tires are cold -- meaning -- not driven far. As the tires warm from friction driving on the road, the air pressure increases. Tire air pressure should be set "cold". Beware to check your air pressure again once the weather gets warmer -- your pressure could then be too high as a result.