The coast is fine. Inland needs a different plan entirely, and it is mostly about the clock.
Summer on the Red Sea coast is genuinely manageable. There is almost always a breeze, the sea is 29°C, and a day on a boat is more comfortable in July than a day on a beach anywhere in Europe. The problem is inland.

Luxor and Aswan reach 45°C in the shade in July and August, and the archaeological sites have no shade at all. A midday visit to the Valley of the Kings in August is genuinely dangerous for older visitors and small children, not merely unpleasant.
The plan that works is to move everything to the ends of the day. Sites open early — be at the gate when they do and be finished by eleven. Sleep or swim through the middle. Go back out after five, when Karnak and Luxor Temple are at their best anyway and the latter is floodlit.


There is almost always a breeze, the sea is 29°C, and a day on a boat is more comfortable in July than a day on a beach anywhere in Europe.
Practically: double the water you think you need, add electrolyte sachets, wear a wet scarf on your neck, and take the overnight versions of the long trips so the driving happens while you sleep and the sightseeing happens at dawn.

