Aswan extremity of Egypt, the river flows for more than without bar or cataract. The voyage from Aswan to Alexandria usually took 21 to 28 days in favourable weather. Aswan has a hot desert climate (Köppen climate classification "BWh") like the rest of Egypt. Aswan and Luxor have the hottest summer days of any city in Egypt. Aswan is one of the hottest, sunniest and driest cities in the world. Average high temperatures are consistently above during summer (June, July, August and also September) while average low temperatures remain above . Summers are long, prolonged and extremely hot. Average high temperatures
Aswan the summer solstice, a vertical staff cast no shadow. They noted that the sun's disc was reflected in a well at noon. This statement is only approximately correct; at the summer solstice, the shadow was only of the staff, and so could scarcely be discerned, and the northern limb of the Sun's disc would be nearly vertical. However, Eratosthenes used this information together with measurements of the shadow length on the solstice at Alexandria to perform the first known calculation of the circumference of the Earth. The Nile is nearly wide above Aswan. From this frontier town to the northern