My thermometer came last night.
Like a complete and total geek I ran around the house randomly zapping all sorts of different things to see what the temperature was.
On a positive note, though, I confirmed that the insulation I added to the attic several years ago was an excellent addition. I never measured the temperature of the upstairs ceiling before I insulated, but it was hot enough that it felt like being under a broiler.
Yesterday afternoon, the temperature on all 4 walls (including one with west exposure) was about 75 degrees. Ceiling temperature was 76 degrees.