Trailer tire pressure in the hot summer

Hello. I am sure this has been asked and I apologize if I am in the wrong section. Do you keep your tires at max pressure during the hot summer? My tires are 50 PSI cold. In the morning I plan to check pressure while it is mild out but then do I pump them to 50, knowing it will get hot and we will be pulling for about 5 hours? Or, do I pump them a little less, knowing they pressure will build with the heat....if so how much less? thanks everyone.