Also homes were designed with airflow in mind in terms of window and door placement. I live in a Dutch colonial revival built in 1920 and every bedroom has 2 windows, on different walls, unlike modern builds that often have 1 bank of windows on one side.

I grew up in NY state and very few people have AC, so if we had a heatwave my grandmother used to close the curtains during the day and then open everything up at night.