In general, the oases share the climate of Nile Valley cities at the same latitude- Bahariya is like Cairo, Kharga like Luxor. But the air is fresher in the oases, and breezes more common. October through April is unquestionably the best time to visit. It is not unusual for summer temperatures, especially at Kharga, to reach the 50°C mark. Even at night, summer temperatures persist into the upper 20s. And you won’t find air conditioning anywhere, making this a much less popular destination in summer. If you go then, finding accommodations will be a cinch.

Check out a copy of Dr. Ahmed Fakhry’s Bahariya and Farafra Oases, an extremely readable introduction to the life and history of these areas. The volume, along with Fakhry’s Siwa Oasis, is published by the American University7 in Cairo Press and is available in the university bookstore on the Old Campus and at several of Cairo’s English-language bookstores (LE9-10 paperback). The university library on the New Campus also has both volumes for consultation.