What to Wear in Egypt — For Comfort, Not Just Custom
Two separate questions get tangled together here: what is respectful, and what will stop you being miserable at midday. The answers overlap more than you might expect.
The comfort case for covering up
Loose long sleeves and long trousers in light cotton or linen are cooler in direct sun than shorts and a vest. This is not a moral point, it is a thermal one.
A wide-brimmed hat matters more than sunglasses. There is no shade at Giza, Karnak or the Valley of the Kings.
Closed shoes, always. Sites are rubble, sand and uneven stone.
Mosques, churches and monasteries
Shoulders and knees covered for everyone.
Women should carry a light scarf for their hair — most mosques provide one but bringing your own is easier.
Shoes come off at the door. Slip-ons save a lot of fiddling.
Beach resorts are different
Hurghada, Sharm, Dahab and Marsa Alam resorts are relaxed. Normal swimwear at the pool and beach is completely fine.
Cover up when you leave the resort into town.