Additionally, the fluctuation in temperature also impacts your tire's psi. The rule of thumb is for every 10 degree Fahrenheit change in ambient temperature, your tire's inflation pressure will change by about 1 psi (up with higher temperatures and down with lower). This means that a properly inflated tire at 85 degrees could lose approximately 5 psi if the temperature were to drop to freezing (32 degrees). To gain a better understanding of how temperature affects your tire's air pressure, read "Air Pressure, Temperature Fluctuations." -
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