Why does heat feel more exhausting here than elsewhere?

You've been in 35°C heat before. You handled it. Here, 35°C puts you on a bench at 2pm wondering if you're ill.

Marrakech heat is a different product. The city sits on a clay and limestone plain that reflects solar radiation back upward. The walls — pisé, stone, concrete — absorb heat all morning and re-radiate it through the afternoon. You are heated from above by the sun, from below by the ground, and from both sides by the buildings. The effective temperature your body experiences can be ten degrees higher than what a thermometer in the shade reads.

Humidity plays both ways. Marrakech is arid — often below 20% relative humidity in summer. Sweat evaporates so fast you don't feel wet, which makes you underestimate how much water you're losing. Dehydration arrives before you notice you've been sweating. The body's cooling system is working overtime, invisibly.

Altitude adds a layer. At 450 meters, UV radiation is measurably stronger than at sea level. You burn faster. Your body expends energy managing UV damage on top of managing heat. The combination — radiant heat from surfaces, invisible dehydration, elevated UV — produces an exhaustion that temperature alone doesn't explain.

Two liters of water a day is a minimum. Three is better. People who've been here a while carry water everywhere and drink before they're thirsty. The thirst signal arrives too late.