25% increase in tire pressure during the day (above max)

I have seen my pressures go as high as 67 and the temps up into the 90's on trips temps are more critical to watch, and realize that the readings will vary from front to back and side to side. The important thing is that they are all in the same general range; ie if all temps are say 89-96 they are in the same range but if one happened to be up over 100 I'd stop to see what was up....perhaps a bearing issue. I also always carry an infra red thermometer to double check the TPMS....sort of belt and suspenders.