When I was a kid growing up in Central Texas we didn't have air conditioning. In the summer we did sleep with the windows and the exterior doors open. There were screens on the windows and at the exterior doors for air circulation. You could sleep well with a lightweight sheet. Being young and being accustomed to spending all the time outdoors that I was allowed, I was totally acclimated to the situation. The worst part of all that were mosquitoes and chiggers in the summer. Once the nights became cool enough to require a blanket we kept the windows closed until things started to warm again in March or April. We had a gas floor furnace that heated the house. On the coldest days all of us could be found in the living room where the floor furnace was located.
By the time I was a teenager we had moved into a house with window units for AC and central heating.
Anything is doable if you are prepared. I suspect a lot of people today have become acclimated to an unnaturally limited temperature range and therefore they can't handle being outside all day in the direct sun without needing a way to cool down. Same thing in winter. People have acclimated to a range of 65-80 and anything outside that range requires different clothing, moving chilled or heated air, etc.
By the time I was a teenager we had moved into a house with window units for AC and central heating.
Anything is doable if you are prepared. I suspect a lot of people today have become acclimated to an unnaturally limited temperature range and therefore they can't handle being outside all day in the direct sun without needing a way to cool down. Same thing in winter. People have acclimated to a range of 65-80 and anything outside that range requires different clothing, moving chilled or heated air, etc.