What's the upper limit for psi (tires) on a 2008 Chevy Impala during this time of year please?

https://ricksfreeautorepairadvice.com/correct-tire...

The tire inflation PSI is listed on the tire spec label in the drivers door opening under the door latch. If the label is missing fill them to 35 PSI. The only "upper limit" there is is on the sidewall of the tire. That is the maximum inflation pressure for when the tire is mounted to the rim. It's way too high a pressure to drive with.

Read the owner's manual or the label on the door frame. This pressures only apply if the car has the STOCK tires on it.  Good luck.

Stick to the pressure listed on the door frame. Listed variations in pressure are related to load not time of year.

It would depend on your specific tires but typically keep your tires for a car like tat at 35. You will have to inflate and deflate around the year when tempeture changes because the air expands depending on the temp. But no matter what type of temp it is it always good to keep it at the reccomended tire pressure which it should say on the side of the tire but most cars that size are 35 psi

Read the drivers manual