Like most people responding to this thread, we aren't saying tire pressure needs to be neglected, but I have never worried about going from 60F to -9F while traveling. Built into the tires are a safe operating range.
We traveled from Arkansas in July to Glacier National park in Montana. On the way back home while in Aspen, CO I checked the tire temperatures and pressure. I was running 19.5" Load Range H tires that had 90 psi in them when I left Arkansas. In Aspen, after a good hard 4 hours of driving, they were showing 105 psi.
When the weather turns colder, I do see a lot of vehicles with under-inflated tires. I check mine between and after oil changes.
The tech at the dealer where I have my oil changed and 23 point inspection performed, lied about the tire pressures. I carried the truck back the next morning and the tech was made to perform the 23 point inspection all over, clean the inside, and wash the outside. Duallys are a hassle to check tire pressure.