Originally Posted by Pompiere

Police: "Ma'am didn't you hear any gunshots?"
Neighbor: "Well I heard a noise, but I thought it was just that guy's bike tires again."

Seriously, the thumb rule for car tires is about a pound for every ten degrees. If you pump them up inside and then go outside, then they will have lower pressure in the cold and come back up when you come back inside. If you pump them up outside in the cold, then you would see the most effect from the thermal expansion. Unless you are testing the limits of the max sidewall numbers, there shouldn't be any issues. A lot of people go well past the max inflation numbers when mounting tires to get the bead to seat correctly.