Does temperature affect tire pressure

Yes, if the weather is hot - Air in the tire will expand slightly and will have an effect on the pressure as it wants to take up more room in size. If the weather is cold the air will contract and more air will be needed - the reason for the extra air is so that the tire doesn't go down. The Math: Pressure increases directly with Temperature. So there's an easy formula to use.

Since 0 psig in a tire is really 14.7 psia and 0oC is really 273oK the temperature and pressure for the tires you fill is Start Pressure = (Pressure on the gauge + 14.7) psia, and Start Temperature = (Measured temp +273) . Temperature at the end = End Temperature = (Measured temp in C + 273), and pressure at the new temperature = End Pressure So: End Pressure = Start Pressure x End Temperature / Start Temperature Since End Pressure includes an extra 14.7 psia, subtract it out and that's the pressure on the gauge in psig.