I am an older northerner (Canadian) living in the south and I find the heat (especially with high humidity) hard to bear but we don't have central AC. Just this summer, we finally invested in a small window ac unit for the bedroom. Till now, we really just rode it out. However, the Siberian was suffering, and the cat wasn't too happy either .. so we gave in to their wishes.
I find it hard to do a lot of cooking in this heat.
I didn't have a/c in even a car till 1996 but I moved to TX that year and I was not able to function at all outside there in the summer so I have succumbed over the years to the desire for a/c indoors.
Now in the mountains of NC, I manage to get through hot days and nights without a/c but I honestly do about nothing during the day when it is very hot and humid. I drink a lot of cold tea (not iced, just refrig temp, no sugar). I use a hot water bottle (with cold water in it) to cool my feet at night - I find that helps to let me go to sleep.
I was outdoors a fair bit in upstate SC today ... and it was not pleasant at all. Even the a/c in the car was not pleasant however because it is not even - if you are hot you blow it on your face or hands to cool off but then you end up with a stiff neck or the rest of you feeling hot by comparison with the body areas where the a/c is directed. Nothing is perfect.
It can and does get as bad (hot and humid) in eastern Ontario as it does here - I didn't tolerate it any better up there really .. though I was younger and that makes a big difference. I never had a/c there either and, as I said, we managed - and dreamt about fall.
MikeK - I have several of those soak/cool scarves too. Great invention - and cheap to make your own. They work wonders.