The rainy season starts in October and about 75 percent of the total rainfall from
November to February, December and January are the rainiest months. The amount of
rain from March on does not exceed 10 percent of the total annual rain. Thus, the dry
season extends for about 7 months. The amount of precipitation is about 180mm per year.
The amount of rain decreases by about 30–50 percent on a distance of about 15Km from
the coast. The yearly mean maximum air temperature is 24 1C and the yearly mean
minimum air temperature is 16 1C. Wind speed ranges from 3.8 to 5.2 m/s The prevailing
wind is mostly from the north.
The soils of the northwestern coast are highly calcareous. This is due to the calcareous
nature of the parent material from which these soils were formed, and the insufficient and
limited leaching. The limited translocation of carbonates, due to the arid climatic
conditions, results in the formation of accumulation zones or horizons. In some profiles