just curious, if i've been driving around for a while and want to check my tire pressure, is there a correct warm tire pressure number above or below which i would be able to tell if my tires are over- or under-inflated? or is checking cold tire pressure the only way to check for proper inflation? thanks!

 

No, there is only a correct cold tire pressure. If it were for track driving the answer would be yes depending on the specific tire. Some R compound tires like more air pressure than others.