If you want great deals on tours and you don't mind blazing hot weather, then visit Egypt in June or September. If you're really brave, head there in July and August, but book a place with a pool and a room with AC.
Find out more about when to go to Egypt below including: Average temperatures; best time to take a cruise on the Nile; best time to visit the Red Sea; best time to visit Egypt's Western desert; Ramadan and travel to Egypt.
Note: The political situation in Egypt after the 2011 revolution means it is a little volatile, see -- Is it Safe to travel to Egypt? for more, and check the local news before you go.
The Weather in Egypt
The weather is the defining factor for most people planning their trip to Egypt. It's hot and sunny for most of the year and there's not much use for an umbrella, unless you use one to protect you from the sun. Winters (November to February) are generally mild although temperatures at night can get down to the 40's Fahrenheit (10 C). Daily temperatures for Cairo during the "winter" are around 70 Fahrenheit (20 C). In the summer months the temperatures reach an average of 95 Fahrenheit (35 C) along with intense humidity to make things even more uncomfortable.
Note when visiting Egypt's ancient sights that they are mostly located in desert areas, despite being along the banks of the Nile River. Climbing into a hot tomb on a 100F degree day is not pleasant. Many of Egypt's top attractions are located in southern Egypt, where it is even hotter than in Cairo. If you are visiting Luxor or Aswan from May through October make sure you avoid the midday heat and get an early start to view the sights.
Best Time to Cruise the Nile
The best time to go on a Nile cruise is between October and April. Temperatures are not too hot during this time of year, since you'll be hopping on and off to check out temples along the way, this is important. The heat in Aswan and in Luxor is intense and it's not recommended that you travel during the peak summer months from June through August. The average temperatures hover over the 100 Fahrenheit mark (40 C). It's even hotter when you're inside some of the tombs around Luxor and there's not a lot of shade around. Check out average temperatures for Aswan (scroll down the page).
The Nile also has a series of locks that take effect in April and June, and may affect your chances of approaching Esna by boat. It takes a while for boats to get through locks, so you also don't want to waste your valuable cruising time waiting in a line of ships for several hours. More information about Tours to Egypt including Nile Cruises.
Best Time to Enjoy the Red Sea
The best time to enjoy a beach holiday along Egypt's Red Sea coast is June and September. You avoid the crowds, the water is warm, and the breeze will keep you cool. Egypt's Red Sea resort towns like Hurghada, are very popular in the winter months, especially with Russian and Eastern European tourists escaping their cold winters. The summer months are also busy with school holidays coinciding with hot weather and warm water temperatures. Temperatures at the Red Sea are actually similar to those in Aswan (scroll down for average temperatures) but a little warmer in winter and a little cooler in summer. Maximum average temperatures in the summer months (May to October) is around 85-90 Fahrenheit (30 C). Winter months (November to February) see average temperatures of around 72-78 Fahrenheit (25 C).
Best Time to Visit Egypt's Western Desert
The best time to visit Egypt's Western desert is October - February, but nights will be very cold. If you're planning a trip to the Siwa Oasis or anywhere west of Cairo in the desert, then the average temperatures for Aswan (scroll down) are a good indicator of what to expect. During March and April a hot wind, known locally as khamsin makes its way across the Western Desert making temperatures rise suddenly and causing mayhem with the sand that blows in with it. You may experience these sandstorms as far east as Cairo.
Traveling to Egypt During Ramadan
Ramadan is the Muslim holy month of fasting and the dates change every year (August 1 - August 30 (2011) , July 20 - August 19 (2012)). Tourists are not expected to fast when visiting Egypt during Ramadan. However, shops and banks tend to close for a longer period of time during the day. Some cafes and restaurants may not open during the day. At night there is a generally festive atmosphere as everyone breathes a sigh of relief and makes the most of being able to eat and drink. There are also plenty of festivities on several nights towards the end of Ramadan that are fun to experience. More about traveling during Ramadan...