27C (80F) at 11pm. Not the kind of temperatures most people consider when they think about arctic living but it's not uncommon to hit the high 20s or even low thirties. Plus the sun is still up and will be up all night, feels a lot warmer. All the buildings are cooking, they generally have atrocious ventilation, metal siding and roofs, and heavy insulation without attic vents. The apartment I lived in when I moved up here was consistently 40 degrees (104F) in 20+ weather, there was no way to cool it down and sometimes you couldn't even turn off the damn heat!! They'd leave it running because it had just snowed (worried about pipes freezing) and no one could be bothered to turn it off for a couple of days.
I know air conditioning is a waste of energy and resources but I just can't sleep without it.
Thinking of the extreme heat that so many regions will have to look forward to due to changing climate conditions is pretty brutal. And A/C is not the answer, it's too power hungry and you can't count on power being available. Using solar panels for power may be a short-term option but a non-technology based solution is ideal. For example, having a basement in your home sure helps, I grew up in Saskatchewan and practically lived in our basement in the summer. Handy for tornadoes too!
Make sure your home is well ventilated, use tinfoil if needed to keep heat from streaming in windows and explore non-powered ways to keep your house tolerable. Trees provide shade and of course other good things - wood, possibly fruit, etc. A good system of window shades or tinfoil will help. If you have pets, children, or elderly people in the home, remember they are all more vulnerable to extreme heat. Make sure everyone stays hydrated, most people don't drink enough fluids - by the time you feel thirsty, you are already dehydrated. The easiest way to check is to see if your urine is clear.