Pack for the Heat
The effect of the Egyptian heat cannot be overstated, especially if you visit during the warmest months of the year, from June to August, when daytime temperatures in Luxor and Aswan consistently reach at least 40°C (104°F) and reach much higher (up to 48°C/118°F) in the Western Desert. Even so, it may be 32°C (90°F) in Cairo and even hotter in the pyramids. Winter temperatures are comfortable, if occasionally chilly at night, and there is minimal rain. Sandstorms are more prevalent in April, but they can happen at any time from March through May.
So, how do you handle these extremes? Ironically, the Egyptians' solution is to cover up even more. Wear a collared shirt (to protect the back of your neck), a hat (preferably with a brim), and a bandana (with which you can mop your brow but also cover your nose if a sandstorm erupts). Linen and lightweight cotton are your friends when it comes to materials, but some of the newest moisture-wicking fabrics may be just as beneficial. Pack plenty of sunscreen because excellent, high-quality sunscreen is hard to come by in Egypt (and when you can find it, it's really costly). And bring a refillable water bottle; while bottled water is available everywhere, it's good to do the world a favor and replenish from a larger (and possibly cheaper) large bottle.