If you have sensors screwed on the outside on the valves, the temperature reading cant be trusted, they give something between outside- and inside-tire temp.
So the pressure then is the only reliable.
But that once you descent from the mountains, and use the brakes to often, the temp in tire can rise to boiling point of water ( 212degrF/100degrC), and with that the pressure rises about 40%.
You can not set your TMPS system that high, so then dont be alarmed if the allarm goes off, you the know its a fals alarm, and better concentrate on the driving.
Normal use when driving about 50mph at outside temp of 65 degrF, the inside tire rises to about 110-120 degr F, and with that the pressure rises about 10 to 11% .
Hottest inside tire temp that is probably still save or tires , so no overheating of rubber , is ( estimated by me) 140 degr F, and it would rise the pressure about a good 15% , but when hotter outside mayby 150degr and more , so when you set it to 15 to 20% upper alarm , I think you are OK.
Then when it goes off, and you suspect other factors ( like that descending from mountains or hot outside temp or sun shining on tire)you yourselfes know its a fals alarm and dont be annoyed by the beeps and ignore them.
But when only driving that alarm, you probably have a problem.
Low alarm can often go off in winter in the morning, because cold temperature outside then same as inside tire , from 65 degr filled goes down about 8% when freesing so 32 degr F outside so inside tire.
So low alarm can do with 10% , or less if you also then realise its from cold outside temp, and ignore it.
When its colder outside the tire can have lower pressure without overheating the rubber when on higher speed, wich is the goal of advice pressure.
Temp differences are larger then, so better cooling down of rubber of tire, wich allows the more heatproduction the more deflection of tire then gives.
