Maximum tyre pressure corresponds to the highest cold pressure possible for the tyre. This pressure should only be used when specified in the user's manual.
In order to get the measurement right, pressure should be checked when cold. It means the tyre should not be exposed to sunlight, and should have stayed immobile for a large period of time.
Hot pressure will indicate a figure that is 4.5 psi higher than the actual pressure..
It means that when cold pressure is equal to maximum cold pressure, when hot, pressure will be higher then the maximum recommended.
Even though you might want to let hot air out and decrease pressure, it is not recommended since pressure will retun to normal when cold without outside intervention.
Please note that maximum pressure for a given load index may have significant variation from tyre to tyre. For example , a standard load tyre should be able to resist pressures up to 35psi. However tyres with a maximum pressure of 45psi are quite common
You find find these values in the owner's manual and on the placard situated on the door jamb.
The maximum pressure that a tyre can resist is indicated in small script on the tyre sidewall. It is indicated in psi