South Africa has a great variety of climate zones, from the extreme desert of the southern Namib in the farthest northwest to the lush subtropical climate in the east along the border with Mozambique and the Indian ocean. From the east, the land quickly rises over a mountainous escarpment towards the interior plateau known as the Highveld. Even though South Africa is classified as semi-arid, there is considerable variation in climate as well as topography.

The interior of South Africa is a giant, rather flat, and sparsely populated scrubland Karoo , which is drier towards the northwest along the Namib desert. In contrast, the eastern coastline is lush and well-watered, which produces a climate similar to the tropics. The extreme southwest has a climate remarkably similar to that of the Mediterranean with wet winters and hot, dry summers, hosting the famous Fynbos Biome. This area also produces much of South Africa's wine. This region is also particularly known for its wind, which blows intermittently almost all year. The severity of this wind made passing around the Cape of Good Hope particularly treacherous for sailors, causing many shipwrecks. Further east on the country's south coast, rainfall is distributed more evenly throughout the year, producing a green landscape. This area is popularly known as the Garden Route.

The Free State is particularly flat due to the fact that it lies centrally on the high plateau. North of the Vaal River, the Highveld becomes better watered and does not experience subtropical extremes of heat. Johannesburg, in the centre of the Highveld, is at 1 740 metres (5 709 ft) and receives an annual rainfall of 760 millimetres (30 in). Winters in this region are cold, although snow is rare.

To the north of Johannesburg, the altitude drops beyond the Highveld's escarpment, and turns into the lower lying Bushveld, an area of mixed dry forest and an abundance of wildlife. East of the Highveld, beyond the eastern escarpment, the Lowveld stretches towards the Indian ocean. It has particularly high temperatures, and is also the location of extended subtropical agriculture. The high Drakensberg mountains, which form the south-eastern escarpment of the Highveld, offer limited skiing opportunities in winter. Many people think that the coldest place in South Africa is Sutherland in the western Roggeveld Mountains, where midwinter temperatures can reach as low as −15 degrees Celsius (5 °F). In fact, the coldest place is actually Buffelsfontein, which is in the Molteno district of the Eastern Cape. Buffelsfontein recorded a low of −18.6 degrees Celsius. The deep interior has the hottest temperatures: A temperature of 51.7 °C (125 °F) was recorded in 1948 in the Northern Cape Kalahari near Upington.