Bernie;
I carry a hand held pyrometer with me. A lot will depend on the ambient temperature. I have seen the temperature vary by 20 degrees from the sunny side of the rv to the shady side of the rv driving down the road. In the summer in Texas when the ambient temperature was over 100 degrees, the tire temp was in excess of 120 and my tire pressure had increased from 110 to 132. On the other end of the spectrum, travelling in temps close to freezing, my tire temp seldom reached 60 degrees.
John