The seasonal weather change, Fall, recently brought Dixie temperatures down ~20F (~10C) and sure enough, our tire pressure alarm came on. Source: Intellicast - Mixed Surface Analysis in United States So I topped them off this morning (i.e., cold tire pressure) and found a 30.5 - 34.0 psi range. If you have tires, cold weather reduces the pressure and leads to more rolling drag. Since the normal threshold is about 10 psi for a low pressure alarm, I like to run door jam +10 psi. When the alarm comes on, the car is at what Toyota thinks they should be. <wink> Bob Wilson
Rule of Thumb - 1 psi tire pressure (up or down) for every 10 degree F ambient temperature change (up or down)
Larger sized tires can be up to 2 PSI per 10°F. I mention this because many here own other vehicles other than Prii.
