The MAx PSI is listed as "Cold" Because : here is an example…you are driving at 55mph on an 80 degree day, the temp of your tires would be in the 130 degree range…you stop and check your tires and find that your one tire is riding at 30 psi when the max cold is 44….so you fill the tire up to 44..with air that is probably not super cold because it is in fact an 80 degree day….Cold tires are usually "cold" at about 50 degrees..and 44 max psi at 50 degrees is the max you should use…if you drive an heat up your tires that are at 44…after a while you will see the gauge up to as high as 60psi or so, But as someone else posted above, about an increase of one psi per ten degrees..it is actually about one percent per ten degrees…so tires at 44 at 500 degrees should babout 50psi at 100 degrees, however, the shape and thickness of tires definitely comes into play in this area, a high performance tire heats up more than a large tread "wrangler" type tire…so in a jeep you may see the psi go to 48-50- where the same psi in a corvette under the same conditions will go as high as 65-70….see next post…