I lived in Fairbanks, AK for 3+ years. It gets hot as hell up there in the summer. It was in the 90s and most places have NO A/C. Add that to the 20+ hours of daylight, wildfires that screw with the air quality so you have to keep your windows closed ... Miserable. No further north, where there's absolutely NOTHING AT ALL, it doesn't get quite as hot. Still ... I'm back in the south, it's 97 degrees F with a heat index of 107. But at least I work in A/C, shop and dine in A/C, and live in A/C.
ETA: The cold was no problem whatsoever. The buildings are built to retain heat. It would be -40 or more and because it was so dry, the cold didn't seem that bad. Besides, you can always bundle up. You can never take off enough to get cool.