Why not follow the tire manufactures recommendations. When they say cold temperature they mean at 70deg F ambient with the tire at ambient temperature. The tire temperature will be above ambient while running. So one must let the tires cool before checking the pressure. My 110 psi tires get 50 deg F above ambient while traveling at highway speeds--and the pressure will be above 120 psi until they cool down to ambient. So it would be stupid to let air out of the tire when they are hot. When the tires are at 40 deg F they are below 100psi and it would be stupid to add more air at that temperature because they would be 110 psi when they get to 70 deg F.