The climate is perfect and the sun is shining for you 99 % of the days of the year. The water temperature of the Red Sea reaches during the summer months reaches a very pleasant 30 °C.
If you have your own diving equipment you should bring a 7 mm Wetsuit in the months December to February, a 5 mm suit from March to June and October to November and a 3 mm wetsuit is fine from July till September.

Every 4 - 5 years it is raining a bit along the Red Sea coast, mainly in November. The Eastern Desert is supposed to flood every 10 years. The wadis (dry river beds) are flooded and a spectacular phenomena happened: the desert burst into bloom!