Why do riads feel cooler inside than outside, even without AC?
The short answer
Thick earthen walls, a central courtyard pulling hot air upward, shade geometry, a fountain adding moisture to the breeze — a riad can sit 10–15°C below street temperature without a single watt of electricity. The building is the air conditioning.
Step through the door. The temperature drops ten degrees in three seconds. Outside, the derb shimmers at forty-four. Inside, the air is cool, still, almost subterranean.
The walls are doing this. They're forty to sixty centimeters of rammed earth or stone — dense enough to absorb heat all day and keep it out of the rooms behind them. By morning, after a desert night that can drop twenty degrees, the walls are cool again. The building resets every twenty-four hours without electricity.
The courtyard is the engine. Hot air rises from the sun-exposed center and escapes upward. Cooler air pulls in from the shaded rooms at ground level. Add a fountain and the evaporating water pulls more heat from the air. Add orange trees and their leaves do the same. The whole system runs on geometry and gravity.
You notice it most at the threshold — that three-second drop when you step inside. By the second day, you stop noticing. By the third day, you step outside and wonder how anyone functions in the heat. The riad has recalibrated your baseline. That's also the design working.