Cameroon Climate

The country's climate is as varied as its topography. Climate ranges from the equatorial heat and humidity of the southern border and the southwestern coast, through a seasonally cooler and drier regime in the central plateau and mountain regions, to the aridity of the northern plain, which lies on the approaches to the Sahara Desert.

The coastal plain is characterized by heavy rainfall, high humidity, and tropical temperatures throughout the year. Inland, on the central plateau, rainfall diminishes, the temperature undergoes seasonal variations, and humidity declines. In the extreme north, near arid conditions exist. Located at the geographical and ethnic crossroads of the African continent, it has great ethnic diversity, which has resulted from the process of intermingling and assimilation that occurred through a history of countless human migrations. The twenty-four major languages and numerous dialects spoken by the country's 200 ethnic groups have served as a divisive element, discouraging interethnic relations. In the modern sector both French and English have official status, a situation unparalleled in any other African country. Inter-regional communication is aided by the use of Wes Cos, a form of pidgin English.

The north is the domain of the Muslim Fulani, who constitute only one-third of the area's population, but it is shared with numerous other ethnic groups. Since their Islamic holy wars of the eighteenth and nineteenth centuries, the Fulani have referred to these other peoples simply as kirdi (pagans). The predominant peoples of the south are the Pahouin, a designation that encompasses a large number of subgroups. The western highlands are shared by the largest of Cameroonian ethnic groups — the Bamileke — and numerous other peoples.

From its northern extremity in the seasonally dry plains of the Chad Basin, the country extends for 700 miles southwestward through regions of upland wooded savanna to the humid mixed forests on the southern plateaus, equatorial rain forest near the southern border, and mangrove swamps along the coast, where rainfall may exceed 130 inches per year. The level of rainfall is the primary factor determining patterns of vegetation and population. Elevation is also significant; areas such as the Adamaoua Plateau and the Bamenda Highlands are high enough to be more comfortable and healthful than the humid forests and lowlands of the southern and southwestern provinces.

The Subarid North

The narrow neck of Northern Province is among the northernmost areas reached by moisture-bearing winds from the equatorial rain belt. Southerly and southwesterly winds bring about forty inches of rain an- nually to the Garoua area and about thirty inches to much of the area farther north. Most of it is concentrated in a five-month season (May to September) in the Garoua region and in a shorter season near Lake Chad. For the rest of the year and intermittently during the rainy season, this northern region is under the influence of drying winds from the Sahara Desert. Surface water is quickly evaporated or escapes through poorly developed soil structures to underground water tables.

Daytime temperatures are usually high except during and immediately after the late summer rainstorms. Midday maximums are often above 90°F, especially during February and March, but nights are usually much cooler, at least during the dry months when the diurnal range often covers thirty degrees and may be as much as fifty degrees. Natural vegetation in most of the area consists of fibrous, hardy grasses, thorny scrub, and low trees, shading into grassier areas south of Garoua, the provincial capital.

Along the northeastern border, the flood plain of the Chari and Logone rivers forms an important subregion. For at least part of the year marsh grasses and a great variety of other swamp plants thrive in waterlogged flood plains that extend for considerable distances north and south of Fort-Foureau. Other swamplands, smaller in total area but having considerable local economic importance, lie east of Garoua along the Benoue River and along one of its major tributaries, the Mayo Kebi.

The Central Savanna

Much of the Adamoua Plateau is an area of humid wooded savanna. At Ngaoundere, a town near the center of the plateau and near the geo- metric center of Cameroon as well, annual rainfall is about fifty-nine inches, twice as much as the average in the far north. The rainy season extends from April to October and is longer toward the south, where this region merges into the region of humid wooded savanna and forests. The central area is a transition zone, a mixture of tropical and equatorial types of vegetation. Elevation as well as geographic location adds to the variety; mountains on or near the plateau may be covered with shrubs and other plants that prefer the cooler climate of the higher altitudes.

Through repeated burning, the original forests have been destroyed in some areas; much of the new growth consists of thorny scrub, marked here and there by fire-resistant trees. Other areas are a type of prairie, in which expanses of grass are interspersed with patches of stunted shrubs.

Much of this subequatorial central area is from 3,000 to 5,000 feet above sea level, and elevation tends to moderate temperatures. Records taken at Ngaoundere (3,600-foot elevation) show average daily maxi- mums ranging from about 82°F in June during the rainy season to 95°F in March at the end of the dry season. Daily minimums are about 60°F or slightly higher during several months of the summer rainy season. Winter is a period of low humidity, which makes the area more com- fortable for humans than the lower and wetter areas in the south and the southwest.

The Humid South

Southward the lower plateaus become progressively more rainy and humid. Between 6°N and 4°N latitude the primary vegetation is a mixture of deciduous and evergreen forest and areas of open grassland that shades into wooded savanna farther north. From the capital city of Yaounde southward and eastward to the national borders, rainfall and warm temperatures foster a perennially green broadleaf forest. Many trees are over 100 feet tall; below them are tangled mixtures of vines, shrubs, and ferns.

Rainfall ranges from sixty inches per year in areas near 5°N latitude to nearly 100 inches in the southern section of the coastal plains near the town of Campo. Diurnal and seasonal fluctuations in temperatures and humidity are within narrow ranges, especially at the lower elevations and along the coast. Yaounde's temperatures are typical, having an average daily maximum of 82°F and an average minimum of 72°F. Relative humidity is not often below 50 percent, and it is frequently above 80 percent. Nevertheless, at 2,300-foot elevation, Yaounde and a large area to the north and east have a more comfortable climate than the southwestern coastal zone.

The southern area comes under the influence of equatorial airmasses from the south as well as Atlantic airmasses from the southwest. Among other complex climatic influences, one result is a pattern that includes two seasonal rainfall peaks annually and two seasons that are less rainy (somewhat inaccurately known as the dry season and the little dry season). The rains are moderately heavy in April and May, tapering off to the little dry season (four to six inches of rain per month) in June and July. Rainfall increases to more than thirteen inches per month in August and September and then recedes to as little as three to five inches per month in December and January.

Coastal and Montane Rain Forest

The climate along the coast is said to resemble a permanent Turkish bath. There is no dry season; temperature and humidity change very little from day to day or from month to month. The western mountains are also a part of this rainy and humid zone, but altitude brings somewhat greater variations in the monotonous patterns of prolonged periods of cloud cover, heavy rain, and high humidity. Temperatures at the port of Douala, in the central coastal area, range from an average daily high of 84°F to average lows of about 72°F; record highs in this area are above 95°F. The average relative humidity is between 85 and 90 percent throughout the year. Rainfall ranges from 100 inches per year south of the coastal town of Kribi to 158 inches at Douala.

Rainfall in the mountainous areas of Southwestern and Northwestern provinces varies greatly. Most areas, including those as far inland as the Bamenda Highlands, receive between sixty and 130 inches of rain per year. Some areas in the coastal plains and in the mountains near the sea receive twenty-five inches of rain per month in August and September, the wettest months.

Mountains in this western region force moisture-laden onshore winds upward into cooler strata, creating local microclimates that are especially wet on their windward sides. The leeward side may be drier than the nearby plateaus or foothills.

Mount Cameroon stands near the coast and catches the full force of the wet winds from the Gulf of Guinea. Turbulence increases as the winds are pushed upward. Rainfall is heavy on the western slopes, sometimes continuing for days at a time. Stations on Mount Cameroon and on the nearby coastal plain are among the wettest in the world; a total of 250 inches per year has been recorded near the mouth of the Wouri River, and over 360 inches in a small area on the slopes of Mount Cameroon.

Because the humidity is high and the rate of evaporation is low, even during months of meager rainfall, most of this zone is covered with a lush and varied vegetation. The most noticeable species in the flat coastal swamps and the various estuaries are mangrove trees; a short distance inland the rain forest includes thich stands of ferns, shrubs, grasses, vines, lianas, palms, various tall hardwood trees, and a wide range of parasitic plants. Farther inland, where there are more changes in slope, elevation, rainfall, and soil, the variety of plantlife is even greater. In some areas gallery forests may block out the sun, even extending their branches across broad stream channels; conversely, open grasslands having few trees are found on some plateaus. In some areas near towns or roads, the original forests have been cut down. Predominant plant types among the new growth may be different from that of the virgin forests, presenting still another variation of the mix.