At what outside temperature are the 32 psi rated?
I noticed that the pressure of my tires can vary 3-4 psi with about 15 to 20 degrees of outside temp. They also go up by the same amount after 30 minutes of use.

 

COLD tire pressure meaning first thing in the morning (usually). it's normal for the PSI to go up as much as 4 psi while driving around. the weather has been wacky recently swinging 20 degrees for a high in 24 hrs in my area...i won't adjust my tire pressure until the temps start to actually stay within a reasonable range as a high/lo (like 10 degrees). it was 60 here to day...it'll be almost 80 tomorrow as a high. it's annoying. PSI can change 1 psi/10 degrees of temp change up or down.

 

I usually set my tires to 32 psi in the late spring to early fall using a tire gauge. The PSI never drops below 32 psi because of the warm temps. I set the tires to 34-35 psi during the winter months with the gauge. When I set my psi to 32 in the winter, the TPMS would alarm when the temps were below freezing in the morning when the TPMS registered below 28 psi.

Another problem I had to adjust for was the +5000ft and the TPMS reading 2-3 psi lower compared to a hand held gauge.