For gases, like air in tyres, temperature and pressure are related. Increase the temperature and the air molecules bounce around faster which increases the pressure. I think this comes under the Gay-Lussac gas law.

For example, pump your tyres to 90psi at 68 deg F then go outside and ride around in 104 deg F weather and the heat will increase the pressure to 97psi

https://en.m.wikipedia.org/wiki/Cold_inflation_pressure