Southern Africa climate
These countries occupy the southern portion of the African continent, approximately south of 18° S. The Republic of South Africa extends from 22 to 35° S. Most of this area and almost all of southern Africa are thus extra-tropical. Much of the interior consists of extensive high plains (known as 'Veld') with an altitude of between 3,000 and 6,000 feet. The interior is divided from the narrow coastal plain by The Great Escarpment forming lofty mountains in the east and south. The eastern shores of southern Africa are warmed by the Agulhas current which flows southwards from tropical latitudes whereas the western shores are cooled by the Benguela Current which flows northwards Antarctica. These influences of relief and ocean currents produce a distinctive pattern of climatic regions.
Both the southerly latitude and the altitude of the interior regions produce a temperate climate such that only the low-lying districts in the north, along the borders with Zimbabwe and Mozambique have a tropical climate. The southern part of South Africa is sufficiently far south to be influenced in winter by weather disturbances associated with the belt of westerly winds in the southern ocean. Because of this, a small area of the south-western Cape Province, below the Great Escarpment, has a Mediterranean type of climate with mild, changeable winters, during which most of the annual rainfall occurs, and a warm to hot, sunny summer. Eastwards of Cape Town, this merges into a region where some rain occurs in all months but where temperature conditions are similar. In the coastlands of Natal and the lowlands below the Great Escarpment up to the Mozambique border (and including Swaziland) the climate becomes almost tropical; winters are warmer and summer is the wetter season.
By contrast the west coast from about 32° S to the border of Namibia with Angola is a desert region with a noticeably small temperature range. Fog and low cloud are frequent along this coast.
In the interior of southern Africa there is a broad contrast between east and west. Total rainfall is greatest in the east and gradually decreases westward so that much of the western Transvaal, Cape Province, Botswana and the whole of interior Namibia is semi-desert with low and unreliable rainfall. The wettest regions are the eastern parts of the Transvaal, Orange Free State, Swaziland and Lesotho, where both altitude and exposure to the moist air coming off the Indian Ocean produce the heaviest and most reliable rainfall. Over the whole of this interior region rainfall comes mainly in the summer season, mostly in thundery downpours. Because of the altitude and the 'continental' influence there is a large daily and seasonal range of temperature so that frost is a frequent occurrence in winter, and snow is common above 5,000 feet. Winters are mostly dry and sunny and the summers are warm and hot.
The greater part of southern Africa has a very sunny climate with much fine and settled weather. The southern coastal regions have their most disturbed and changeable weather in winter whilst the eastern coastlands and the interior have their most disturbed and rainy weather in summer. In very few parts of southern Africa are the weather and climate unhealthy or likely to cause great discomfort or stress. Daily sunshine levels are high over most of South Africa, averaging eight to 10 hours a day all year round.