Oh dear! This is going to sound pompous but those who know me will tell you that is not my thing. However, when it comes to pressures and temperatures there is a thing called Boyle's Law, which can be written as
P1V1 + P2V2
T1 T2
where P is pressure, V is volume and T is the temperature(in degrees absolute
The volumes can be considered constant as the tyre does not change its size significantly. If we start off with a tyre at 7 deg C, i.e. 280 deg absolute and then increase the temperature to 27 deg C i.e. 300 deg absolute then the pressure will go up by 300/280 = 1.07
So if you start off at 30 lbs/inch squared it will go up to 32.1 lbs/inch squared.