Ça fait dix mille ans qu’il ne pleut pas dans le Sahara ? Mais à Gizeh où sont le sphynx et les pyramides ? Allez donc voir ici http://en.wikipedia.org/wiki/Giza et cherchez "climate". Vous trouverez

Climate

Giza experiences an arid climate (Koeppen BWh), but often with high humidity due to the Nile River Valley’s effects. Wind storms can be frequent, bringing Saharan dust into the city during the months of March and April. High temperatures in winter range from 12 °C (54 °F) to 17 °C (63 °F), while nighttime lows drop to below 7 °C (45 °F), often to 5°C ; the lowest recorded temperature was 0.8 °C (33 °F). In summer, the highs rarely surpass 40 °C (104 °F), and the lows drop to about 20 °C (68 °F). Rainfall is sparse, but sudden showers do cause harsh flooding. Hail and sleet might take place.

Traduction des deux dernières phrases : les précipitations sont rares, mais les averses soudaines causent de sévères inondations. Il peut grêler et verglacer.