External temperature don't cause that much pressure change, unless it's a dramatic 25 degrees change, think +/- 5 PSI.. The biggest effect is from speed and weight. I don't know on bike, but on car, driving 1 mile at 55 mph, increases temperature such that new pressure is measured 5 PSI more.


It's how most tires get worn and accidents happen. People drive to get air, and them inflate hot tires. They get cold and tire becomes underinflated. Less traction, less responsive steering.