Is that after driving and then sitting? Because I drag race I know that tire will go up between 3 - 8 PSI after a run I do not burn my tire just dry hop. Now the cold will not let then go up as much but it depends on how you drive the roads, what PSI is in the tires. How they sit in the sun & what side is in the sun. How long they sit in the shade. The best way is to take you tire PSI at morning after you know there all set to the same PSI mark it down, before you go on your norm drive after you get there take PSI again mark it down after work take it again then 10 minutes after again mark it down. Do this the next day take note that the weather is close to the same. To try seeing what is for the norm for your tires, now keep in mind hard braking or harder then take off will make the temp change a little. After you get a base range PSI if they go down a lot more norm, then your tire need to be inspected or your valve, rim. But you have to know that these three things are good! Before you can get the Base line for the PSI of what you tire lose to cold and heat up and cool down. So the best time is in the morning and 15 min after cool down for taking tire PSI then it should be close to what it will be in cold temps. Once you know what the temp range is heat up and cool down you can set your PSI try to sit it in the closes range for the tire to get best traction. All so you will know if it is lower than the norm at cold temps ( as get colder it may make the tire lower ) Oh do not forget front can take a little bit more sometime because car is heavier in front then the rear and rotate tires at proper time to get longer tire life. In summer you may need to let out a little bit out but only in the cooler times. If you let or put air in the tire on a hot tire or cold tire if you take the PSI at a different time at the end of the day or the next you take your PSI may read lower cold after the last time you let air out. So you have to take into account how much your tire drops in PSI after the day or the run after the cool down of normal day. Or the heat up after a normal drive so you know how much it will drop back to when it cool.