Africa’s climate is unlike that of any othercontinent for several reasons. The most impor-tant is the fact that the entire continent is within the tropical zone. The equator bisects the continent; therefore, in the areas north and south of the equator, the climates are similar, yet they differ because the region north of the equator is much larger than the southern region. Since the northern area is so broad in the east-west direction, maritime effects inland are minimal. Also, an extensive low-pressure area develops inland due to extreme land mass heat-ing. The southern section, however, with its maritime influences is dominated by a belt of high pressure during winter and by low pressure during summer.
Another factor is the cold currents whichexist along its western shores. These currents allow an influx of cool winds and associated weather to the west coast. The final factor involves the lack of high mountain ranges common to other continents. Since there are no prominent mountain ranges, the various climate types in Africa blend together, showing no sharp distinctions.
The most important climatic element inAfrica is precipitation. Precipitation is greatest near the equator (60 to 80 inches to over 120 inches in places). It decreases sharply to the north (less than 10 inches), and de-creases gradually south of the equator (average of 20 to 40 inches). Because Africa is in the tropical zone, the precipitation belt of the intertropical convergence zone (ITCZ) moves with the seasons. This belt of precipitation moves northward in the summer and southward in the winter.
Africa does have distinct climatic regions.Air-mass movement and influences allow for a division of eight climatic regions.
The northern region includes the great Saharadesert. The desert is a source region for dry continental-type air masses. While maritime air may transit the area, the air masses are highly modified and often exhibit continental properties after moving inland. This desert region is extremely hot during the day through-out the year but is very cool at night due to a lack of moisture; hence, strong, radiational cooling.
The southwest region is an arid to semiaridarea which is known as the Kalahari Desert. The temperatures are not as extreme as in the Sahara because the land area involved is much smaller.
North Central Region
The north central region is a semiarid area located along the edge of the Sahara. While the temperatures are similar to those of the neighboring desert (50°F in winter to well above 80°F in summer), this area occasionally gets precipitation in the winter. The source of this precipitation for the northern area is mari-time air from the Mediterranean; in the south, it is the spotty rainfall provided by the meandering ITCZ.
The sub-equatorial region extends towardthe equator from the semiarid region in the north. The region is marked by seasonal rainfall associated with the position of the ITCZ. The region is wet for about 5 months (Nov-Mar) and dry during the rest of the year. Temperatures show little seasonal variation (68°F to 86°F) because of the close proximity to the equator. The only exception to this temperature stability occurs in the western portion which, during the winter, is occasionally influenced by cool weather from the north.
The equatorial region includes the southwesttip of northern Africa and the region between 5° north and south latitudes, extending from the west coast to Lake Victoria. It is the wettest climate in all Africa. These areas have two distinct rainy seasons associated with the northward and southward movement of the ITCZ. Rainfall averages over 120 inches annually in some areas. Throughout the rest of the year, precipita-tion remains plentiful because of the influx of maritime air from the west. There are no significant mountains in the region to prevent this maritime air from migrating inland. Temperatures are moderate year round.
Southeast Coastal Region
The southeast coastal region has a humidsubtropical climate. This region has rainfall all year (45 inches on the average) and temperatures remain generally moderate all year, ranging from an average maximum of 72°F in winter (July) to 89°F in summer (January).
Southeastern Interior Region
This region has a wet-and-dry type of maritimeclimate; however, it is considered temperate because of the lower temperatures common to the higher elevation.