The Saharan region covers roughly the northern third of the country, including Borkou-Ennedi-Tibesti Prefecture along with the northern parts of Kanem, Batha, and Biltine prefectures (see fig. 1). Much of this area receives only traces of rain during the entire year at Faya Largeau, for example, annual rainfall averages less than three centimeters. Scattered small oases and occasional wells provide water for a few date palms or small plots of millet and garden crops. In much of the north, the average daily maximum temperature is about 32° C during January, the coolest month of the year, and about 45° C during May, the hottest month. On occasion, strong winds from the northeast produce violent sandstorms. In northern Biltine Prefecture, a region called the Mortcha plays a major role in animal husbandry. Dry for nine months of the year, it receives 350 millimeters or more of rain, mostly during July and August. A carpet of green springs from the desert during this brief wet season, attracting herders from throughout the region who come to pasture their cattle and camels. Because very few wells and springs have water throughout the year, the herders leave with the end of the rains, turning over the land to the antelopes, gazelles, and ostriches that can survive with little groundwater.

Data as of December 1988