I can relate. I did more than a few roofs in high school and college. I remember the heat, the salt tablets, and being absolutely crusty with dried sweat at the end of the day. I do reminder how much better the shingles went on when they were hot. I never did any barns though. That is a whole other level, though I am sure techniques have improved a lot.
Definitely made me realize that my strong suit wasn't bucking shingles up on to roofs and nailing them down, though it was fun and certainly got me in better shape. I always think roofing is one of those glory jobs. Houses look so much better afterwards.
We are getting a mini heat wave; it was 81F at seven this morning, (vs 56F normally), and supposed to be mid nineties later. The weekend is forecast to be even hotter, but nothing like what the PNW went through.
All the best,
Peter