Eritrea is located in the north-eastern part of Africa and covers an area of 124,320 km2. It is bounded by the Sudan in the west and north-west, Ethiopia in the south, Djibouti in the south-east, and the Red Sea in the east (FAO/ Sectoral review, 1994). Administratively, Eritrea is divided into six zones (zoba) namely: Makel, Debub, Gash-Barka, Anseba, Semenawi Keih Bahri, and Debubawi Keih Bahri.
The country is divided into six agro-ecological zones. These are: the Central Highland Zone (CHZ), situated at altitudes over 1,500 m with over 500 mm of rainfall; the Western Escarpment Zone (WEZ), situated at altitudes between 750 and 1,500 m with annual rainfall between 400 and 600 mm; the South Western Lowland Zone (SWLZ), situated at altitudes between 600 and 750 m, with annual rainfall between 500 and 700 mm; the Green Belt Zone (GBZ), located between 750 to over 2000 m, with rainfall from 700 to more than 1000 mm; the Coastal Plain Zone (CPL), from below sea level to 600 m, with less than 200 mm rainfall; and the North-Western Lowland Zone (NWLZ), with an altitude from 400 to 1,500 m, and up to 300 mm of rainfall.
Due to its geographical setting, Eritrea has diverse climates ranging from hot arid, adjacent to the Red Sea to temperate sub-humid in isolated micro-catchments within the eastern escarpment of the Highlands. About 72% of Eritrea is classified as very hot, with mean annual temperature exceeding 24oC, while not more than 14% is classified as mild or cool with mean annual temperature below 21.5oC (FAO, 1996).
Most parts of the country receive rainfall from the south-west Monsoon, from April to September. Some rain falls in April/May while the main rain starts in June, with the heaviest precipitation in July and August. Only the coastal plains and the central part of the eastern escarpment of the central highland have winter rainfall, November through March, that is borne by north and south-east continental air streams that carry little moisture until affected by the Red Sea. The total annual rainfall tends to increase from north to south, from less than 200 mm at the northern border with the Sudan to more than 700 mm in the south-western part of the country. The Green Belt Zone receives the highest annual rainfall averaging about 900 mm (FAO, 1994).
