The subtropical location, on either side of 30° S, accounts for the warm temperate conditions so typical of South Africa, making it a popular destination for foreign tourists.
The country also falls squarely within the subtropical belt of high pressure, making it dry, with an abundance of sunshine.
The wide expanses of ocean on three sides of South Africa have a moderating influence on its climate. More apparent, however, are the effects of the warm Agulhas and the cold Benguela currents along the east and west coasts respectively. While Durban (east coast) and Port Nolloth (west coast) lie more or less on the same latitude, there is a difference of at least 6° C in their mean annual temperatures.
Gale-force winds are frequent on the coasts, especially in the south-western and southern coastal areas.
South Africa has an average annual rainfall of 450 mm, compared with a world average of 860 mm. About 65% of the country receives less than 500 mm per year, which is generally accepted as the minimum amount required for successful dry-land farming.
About 21% of the country, mainly the arid west, receives less than 200 mm per year.
In Cape Town, the capital city of the Western Cape, the average rainfall is highest in the winter months, while in the capital cities of the other eight provinces, the average rainfall is highest during summer.
South Africa’s rainfall is unreliable and unpredictable. Large fluctuations in the average annual rainfall are the rule rather than the exception in most areas of the country.
Below-average annual rainfall is more commonly recorded than above-average total annual rainfall. Drastic and prolonged droughts periodically afflicts South Africa. These droughts often end in severe floods.
Temperature conditions in South Africa are characterised by three main features: they tend to be lower than in other regions at similar latitudes, for example, Australia, due primarily to the greater elevation of the subcontinent above sea level; despite a latitudinal span of 13°, average annual temperatures are remarkably uniform throughout the country; and there is a striking contrast between temperatures on the east and west coasts.
Owing to the increase in the height of the plateau towards the north-east, there is hardly any increase in temperature from south to north.
Temperatures above 32° C are fairly common in summer, and frequently exceed 38° C in the lower Orange River Valley and the Mpumalanga Lowveld.
Average temperatures (°C) in South Africa
Frost often occurs on the interior plateau during cold, clear, winter nights, with ice forming on still pools and in water pipes. The frost season (April to October) is longest over the eastern and southern plateau areas bordering on the escarpment. Frost decreases to the north, while the coast is virtually frost-free.
Average annual relative humidity readings show that, in general, the air is driest over the western interior and the plateau. Along the coast, the humidity is much higher, and at times may rise to 85%. Low stratus clouds and fog frequently occur over the cool west coast, particularly during summer. The “mist belt” along the eastern foothills of the escarpment is the only other area that commonly experiences fog.
South Africa is famous for its sunshine. Generally speaking, April and May are the most pleasant months when the rainy season over the summer-rainfall region has ended, and before the rainy season in the winter-rainfall area has begun. At this time of year, the hot summer weather has abated and the winds are lighter than during the rest of the year.
In certain areas, however, notably the hot, humid KwaZulu-Natal coast, Mpumalanga and Limpopo, June and July are the ideal holiday months.