YOUNGSTOWN, Ohio (WKBN) — One of the earliest indicators of colder temperatures is low tire pressure in your vehicle, but what causes this phenomenon? Do you remember anything from your high school chemistry class? That is where today's lesson comes from. What causes low tire pressure when it's cold? Car and truck tires are filled with air, which is a gas. The temperature and pressure of gases are directly related to each other, which means that when the temperature of the gas increases, so too does the pressure. When the air temperature cools off in the fall months, the air pressure inside of a tire also decreases, because of this relationship. Animation showing the relationship between temperature and pressure of a gas. (NASA.) The relationship described above is known as Gay-Lussac's Law, which is named after the French scientist Joseph Louis Gay-Lussac. The temperature of a gas is a measure of how fast molecules are moving throughout the gas itself. Higher temperatures mean that the molecules are moving faster, and vice versa. Similarly, the pressure of a gas is a measure of the force with which these molecules strike the walls of a container (in this case, a tire). The faster the molecules move, the stronger the force and the higher the pressure. Do you really need to let your car warm up before driving in winter? Changes in temperature can, of course, then have an impact on your tires. A temperature drop of 10 degrees can result in a pressure drop in your tires of 1-2 psi. How can you prevent low tire pressure in cold weather? Low tire pressure can lead to multiple issues, including decreased gas mileage, traction issues during rain or snow, and damage to your tires. It is important to make sure your tire pressure is where it needs to be to avoid these things. Why letting EVs warm up in the cold can backfire First, you need to be aware of the standard tire pressure is for your vehicle. This is usually located inside the driver-side door, and it will typically be a number between 30 and 35 psi. You can check this using a tire pressure gauge. If the pressure is low, you'll want to fill the tires back up to the pressure listed on the car door.