Four Major Zones

Physical Geography
The climate of Mauritania is mostly dry and hot. The northern portion of this barren country is covered by the Sahara desert. This part of the country has an average temperature of over one hundred degrees and gets almost no precipitation. The whole country gets on average 500 to 600 millimeters of rain fall.
Mauritania has four major geographical areas. There is the Saharan, Sahelian, Senegal river, and coastal zones. Sand covers forty percent of the country.there are two types of dunes, mobile and fixed dunes. Fixed sand dunes are composed of coarse, fawn-colored sand, while mobile dunes consist of fine, dust like, reddish-colored sands that can be carried by the wind. Plateaus generally are covered with heavier blue, gray, and black sands that form a crusty surface over layers of soft, loose sand.These dunes are almost everywhere except in the Senegal river Valley.

The Sahelian Zone goes south of the Saharan Zone to about thirty kilometers of the Senegal River. Its made up of steppes and savanna grasslands. Herds of cattle, sheep, and goats move across this zone in search of pasturage. The hivernage begins earlier in the Sahelian Zone than in the Saharan Zone, often lasting from June until October. Because farmers and herders depend on annual rains. If it starts one month late in the beginning of the rainy season it can cause large losses.

The climate of the Senegal River Valley is simalar to that of the Saharan and Sahelian zones. Rainfall is higher than in other regions, from almost 400 millimeters to 600 millimeters on average, between May and September. This rainfall, combined with annual flooding of the river, provides the basis for agriculture. Temperatures are cooler and subject to less annual and diurnal variation than in

The Coastal Zone spans approximately 754-kilometer-long Atlantic coast. Prevailing oceanic trade winds from the Canary Islands modify the influence of the harmattan, producing a humid but temperate climate. Rainfall here is minimal; in Nouadhibou it averages less than three centimeters annually and occurs between July and September. Temperatures are moderate, varying from mean maximums of 28°C and 32°C for Nouadhibou and Nouakchott, respectively, to mean minimums of 16°C and 19°C.