The Republic of the Sudan, located in north-eastern Africa, lies almost entirely within the tropics between latitude 21° 55´ and 3° 53´ N and longitudes 21° 54´ and 38° 31´ E. It is bounded on the north by Egypt; on the east by the Red Sea, Eritrea, and Ethiopia; on the south by Kenya, Uganda, and the Democratic Republic of the Congo (DRC, formerly Zaire); and on the west by the Central African Republic, Chad, and Libya. It is the largest country in Africa (2 505 813 km2). Of this, 29% is usually classified as desert, 19% as semi-desert, 27% as low rainfall savanna, 14% as high rainfall savanna, 10% as flood region (affected by floods and swamps) and less than 1% as true mountain vegetation.
Generally speaking the landscape is a basin-like plain with an elevation between 300 to 900 meters. There are a few groups of hills and a mountain range in the south, the Imatong Mountains, rising to over 1 500 m; Djebel Mara mountain (3 090 m) in Darfur province in the west and the Red Sea Hills (over 2 000 m) in the north-east near the coast. The highest point in Sudan, Kinyeti (3 187 m), is in the southeast.
The country can be divided into three natural regions. North of Khartoum is primarily desert. The central part of the country is mostly a grass-covered plain. The south contains a vast swamp, the Sudd, and rain forest.
Almost the entire drainage of the country is from south to north through the Blue and White Niles and the Sobat and Atbara Rivers. The Nile River is called the Bahr al Jabal in southern Sudan. North of the Sudd, the Bahr al Jabal is called the White Nile. It meets the Blue Nile, which flows from the mountains of Ethiopia, at Khartoum to form the main Nile River.
Sudan has a range of tropical continental climates with large daily and seasonal fluctuations in temperature. In the deserts, winter minimum temperatures as low as 5° C are common at night, while summer maximum temperatures often exceed 44° C. In the vicinity of Khartoum the average annual temperature is about 27° C. Temperatures, humidity and rainfall are all higher in the south.
There is a large variation in annual rainfall, from less than 75 mm in the desert, 75 mm to 300 mm in the semi-desert, 300 mm to 1 500 mm in the woodland savannas and to over 1 500 mm in the montane vegetation. Dust storms, called haboobs, occur frequently.
The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.