The Western Cape's wine regions stretch 300 kilomers from Cape Town to the mouth of the Olifants River in the north, and 360km to Mossel Bay in the east. Areas under vine are rarely more than 160km from the coast. Further inland, the influence of the semi-arid Great Karoo Desert takes over. The climate can be cool and rainy (as in Cape Point and Walker Bay) but is more often Mediterranean in nature.
The Western Cape is littered with spectacular mountain ranges that form the Cape Fold belt. These are extremely important for viticulture across the whole region, contributing soils and mesoclimates ideal for the production of premium wines. Of particular importance are the Boland Mountains, which form the eastern border of the Coastal Region, and the Langeberg range, which separates the Breede River Valley from the Klein Karoo semi-desert. The Hottentot Hollands and the Riversonderend mountains around Elgin and Overberg are also very influential on the wines produced in those regions. The Cederberg Mountains in the north are home to some of South Africa's highest-altitude vineyards. The dominant soil types in the Western Cape are granite, Malmesbury shale and Table Mountain sandstone. Alluvium and loam soils can be found along the beds of the Breede River, the Berg River, and the Olifants River in the north.
The surrounding oceans play a big part in the climate of the Western Cape. The area between Cape Point and Cape Agulhas is where the Antarctic Benguela Current of the Atlantic meets the warmer Agulhas Current of the Indian Ocean. The prevailing winds that blow in from the south-east – collectively known as the 'Cape Doctor' – are cooled by these currents, bringing refreshment to vineyards across the Cape. Westerly winds that affect the more-northern areas of the Cape are also cooled by the Benguela Current, which runs all the way up the west coast of South Africa.