Africa lies between 37N and 35S.  Because of this Africas climates are almost symmetric if you were to fold it along the equator.  The climate zones are determined by latitude, except for the east.  In the east highlands greatly modify the climate.  Africa is the most tropical of the 7 continents, only its northern and southern extremes are directly influenced by mid-latitude westerly winds and are considered to have temperate    climates.

Most of the African continent lies between the Tropic of Cancer and the Tropic of Capricorn and has high temperatures throughout the year.  The only way to tell the difference of the climates is by the amount, duration, and seasonal distribution of rainfall.  Africa in this sense has six (6) climates:  tropical wet, tropical summer rainfall, semiarid, arid, highland, and Mediterranean. 

The tropical wet climate is around the equator in the west and center part of Africa, and also in Madagascar.  Rainfall is usually very high exceeding 1,500 millimeters (60 inches) a year, and in some areas rainfall is as high as 2,300 millimeters (130 inches) a year.  Rainfall in the tropical wet climate occurs at least once a month if not more, and many areas experience very rainy periods in the spring and fall.  Temperatures in a tropical wet climate remain at a year round average of more than 27C (81F) and rarely drop below 21C (70F).

Tropical summer rainfall climates, also known as tropical savanna climates, occur north and south of the tropical wet zone, in much of West Africa and southern Africa and most of Madagascar. This climatic zone is marked by a well-defined dry season of three to eight months. Annual rainfall is usually between 500 and 1,500 mm (20 and 60 in), although limited areas have considerably morefor example, Freetown, Sierra Leone, averages 3,800 mm (150 in) per year. The tropical summer rainfall zone is a transitional zone between tropical wet and semiarid zones, so there is a progressive decline, moving poleward, in total rainfall and the duration of rainfall. Areas with a longer rainy season tend to have two rainy periods separated by a short dry spell, while areas with a shorter rainy season have a single rainy period. Temperature ranges in the tropical summer rainfall zone are slightly higher than in the tropical wet zone, and increase with distance from the equator. In the northern section of this zone, daily high temperatures average more than 30°C (90°F) over the course of the year. Temperatures in the southern and eastern sections of this zone tend to be cooler because of higher altitudes (MSN Encarta® Quote.).

Surrounding the tropical rainfall zone are areas of semiarid and arid climates in north central Africa, east central Africa, and southern Africa.  The semiarid, also known as the hot steppe, zone has a short rainy season usually only lasting for about 3 months.  During those three months the rainfall usually averages 250 millimeters to 500 millimeters (10 inches to 20 inches) of rain per year.  Precipitation is very scare and unreliable, because of this it creates difficult conditions for plant growth.  Temperatures vary in the semiarid zone with average daily highs of 25C to 36C (77F to 97F).  Africas arid region receives very little rainfall.  These regions might be classified has hot deserts, but there is significant temperature variation and fluctuations in a day.  In the Sahara, summer daytime temperatures can become so hot they exceed 50C (120F), and during the winter nighttime temperatures can drop below freezing!

 In East Africa tropical highland climates are very common.  Temperatures in the highlands of Ethiopia and Kenya average 16C to 21C (60F to 70F), on average 5 Celsius degrees (9 Fahrenheit degrees) cooler than the lower plateaus of such countries has Kenya, Uganda, and Tanzania.  In most of the world higher elevations receive more precipitation than the lower elevations, but the highlands in East Africa are an exception.  It is an exception because they receive lower levels of rainfall.  But the high mountains on the southeastern flank of the Ethiopian plateau receive greater precipitation amounts on their windward slopes.

The coastal areas of the Cape region of South Africa and the North African coast from Morocco to Tunisia have Mediterranean climates.  The Mediterranean climates have very mild and rainy winters followed by warm and dry summers.  These areas receive an average of 250 millimeters to 1,000 millimeters (10 inches to 40 inches) of rain annually.

African vegetation zones are closely linked to climatic zones, with the same zones occurring both north and south of the equator in broadly similar patterns. As with climatic zones, differences in the amount and seasonal distribution of precipitation constitute the most important influence on the development of vegetation. Moving across the continent into drier and drier climates, the typical sequence of vegetation is from tropical moist forest to moist savanna, dry savanna, semi-desert, and finally desert (MSN Encarta® Quote).

Tropical moist forest occurs in humid tropical areas, usually with 1,500 mm (60 in) or more of precipitation and a dry season (or seasons) of three to four months or less (MSN Encarta® Quote).  West of the highlands of East Africa and centered in the basin of the Congo River is a tropical moist forest extending about 600 kilometers (400 miles) north of the equator, and about 600 kilometers (400 miles) south of the equator.  On the west side of the forest it extends to the Atlantic Coast of Congo, Gabon, and Cameroon, and stretched in an uninterrupted belt along the West African coast to Sierra Leone.  Tropical moist forests also occur along the eastern side of Madagascar.

There are two major subtypes of tropical forest that scientists recognize, and those are:  tropical rainforest and tropical wetland forest.  Tropical rainforests are characterized by dense masses of evergreens, oil palms, and numerous species of tropical hardwood trees divided vertically into strata, or layers.  The upper canopy of treetops, in a tropical rainforest, forms a dense cover over the middle layer of treetops and it also forms over the ferns, shrubs, and mosses on the lower level.  Rising above the canopy are scattered tall trees, taller than the canopy, known has emergents.  In dense forest environments the shrub layer tends to be very sparse, an exception of this is along streams.  The reason it is so sparse is because the canopy limits or controls the amount of sunlight that makes it to the forest floor.  Tropical rainforests have an extremely diverse life of species for plants (and animals), but pure stands of a single species are rare.

Tropical wetland forests include both fresh and saltwater subtypes.  The freshwater swamp forests cover big areas of the Middle Congo River Basin.  Saltwater swamp forests occur mainly between Senegal and Angola on the Atlantic Coast and between South Africa and the Red Sea on the coast of East Africa.  Mangrove species of trees are very common in the swamp forests and wetland areas and can grow up to 75 feet tall.  Many of them have been cut down, especially in West Africa, to make room for rice cultivation. 

Surrounding the central tropical forest zone on the north, east, and south is a zone of tropical savanna vegetation that covers up to 65% of the continent.  The savannas are a somewhat drier climate then the tropical forests.  Typically, a savanna climate receives between 500 millimeters to 1,500 millimeters (20 inches to 60 inches) of precipitation per year, and have a pronounced dry season, usually it lasts anywhere from 3 months  to 8 months.  Moving poleward, savanna vegetation transitions from moist woodland savanna to dry woodland savanna.

Most of the woodland savanna occurs very near to the tropical forest, where the climates are wetter and the dry season only lasts for 3 months to 4 months.  The characteristic vegetation is a mixture of tall grasses and closely spaced trees.  Vegetation is very dense along rivers and streams, with trees lining the banks in gallery forests.  Shrubs and grasses are also intense along areas where very intensive cultivation and past use of fire to clear vegetation have led to the degradation of forested land.  Shea trees are very common.  Shea trees have a tough outer bark that is fire resistant and the kernels of the Shea tree are used in oil for cooking and other uses.

Dry woodland savanna is also known has Sudan Savanna.  A dry woodland savanna occurs when there is less precipitation and a prolonged dry season of about 5 months to 8 months. As the precipitation declines, so does the density and amount of grasses, trees, and tree cover becomes less dense too.  The baobab is the largest tree in the dry woodland savanna.  The baobab is widely distributed and is valued for its inner bark (which can be made into rope) and its edible leaves and fruits.  Other common trees are the silk cotton and locust bean, and there are also various species of acacia and fig (ficus) families.

In the semi-desert, or steppe, zone that lies between the dry woodland savanna and the desert, annual precipitation is between 250 and 500 mm (10 to 20 in). Rainfall is limited, localized, irregular, and often violent. Semi-desert vegetation fringes the Sahara on the south (where this zone is referred to as the Sahel savanna), north (especially the southern slopes of the Atlas Mountains) and east (on the Red Sea coast). It also occurs in Somalia and northeastern Kenya, in the Karoo plateau regions of South Africa, and on the inland margin of the Namib Desert of Namibia and Angola. In addition, the Kalahari Desert is actually a semi-desert region, despite its name. In many of these areas, vegetation occurs in strips running along contours in the land, where there has been an accumulation of moisture and soil. These vegetated strips are usually separated by wide barren areas.

Plants living in the semi-desert or steppe zone have to be able to survive off of very little amounts of water.  Trees must also be adapted to survive long periods without water.  These trees have deep root systems, thick bark, small leaves that may shred, and thorns to discourage animals from feeding on them.  With still greater aridity, only grasses and dessert shrubs will survive.  Semi-desert, or steppe, vegetation is vulnerable to fire, clearing for cultivation, and overgrazing.

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