Aswan Dam assumption did not take into account the extent of perennial irrigation that was already present throughout Egypt decades before the high dam closure. By the 1950s only a small proportion of Upper Egypt had not been converted from basin (low transmission) to perennial (high transmission) irrigation. Expansion of perennial irrigation systems in Egypt did not depend on the high dam. In fact, within 15 years of the high dam closure there was solid evidence that biharzia was declining in Upper Egypt. S. haematobium has since disappeared altogether. Suggested reasons for this include improvements in irrigation practice. In the Nile Delta,
Aswan remain above during the coldest month of the year while average low temperatures remain above . Winters are short, brief and extremely warm. Wintertime is very pleasant and enjoyable while summertime is unbearably hot with blazing sunshine although desert heat is dry. The climate of Aswan is extremely dry year-round, with less than of average annual precipitation. The desert city is one of the driest ones in the world, and rainfall doesn't occur every year, as of early 2001, the last rain there was seven years earlier. Aswan is one of the least humid cities on the planet, with an