A few years back I spent a very warm week in Rome with my family. It was still "Spring" according to the calendar, but the temperature was a steady 90+degrees, making mid-day sight seeing a bit of a challenge. Staying inside the small rental during peak sun helped, especially because of this shade seeking practice.
I noticed that many of the apartments surrounding us had heavy retractable awnings that fully covered their windows during the morning and afternoon sun. Some units would leave a small gap for air flow, while others would cover up completely, as the air was often incredibly warm and humid. In the evening the windows would fling open letting a cooler breeze circulate.
This principle really stuck with me after that trip—seeing a whole city relying on this natural method of keeping cool was very inspiring. When the summer sun arrives I now make a point to keep the curtains drawn. And on those all but unbearable days, my windows and doors are shut tight too!