In contrast to the rest of the South Africa, most of the Western Cape experiences a maritime Mediterranean climate*, with the winter months wet and cool, the summer hot and dry. In general, levels of precipitation range between 300mm along the coastal bands to 1,500mm plus in inland high altitude areas, most of which falls between June and August, when rain carrying north-westerly winds prevail. The temperature at this time ranges between 7 °C and 17°C. Things warm up between November and March, with temperatures averaging in the mid-twenties.
However, the combined effect of the Benguala and Agulhas currents and an extremely varied topography means that micro-climates abound, temperatures vary and levels of precipitation across a few kilometres depend on local altitudes. What follows, therefore, is a brief look at the climate and how it influences travel in just those destinations currently (2011) used by Journeys by Design. They are: Cape Town, Table Mountain, the Winelands, the stretch of coast between Cape Town and Walker Bay, Cedarberg Mountains and the beginnings of the Garden route, from Heidleberg to Plettenberg Bay**.
The Cape Town bowl receives an average of 515mm rain per year. Temperatures range between an average of 11.4°C and 22°C, the months between May and October cooler, those between November and May exacerbated by the Berg Winds, which bring added heat (from the Western Cape Karoo) in January and February, and by the dry south-easterly winds, known locally as the Cape Doctor - it helps reduce the city’s levels of dry season pollution. As a result of the above mentioned oceanic currents, water temperatures depend on location, with the western Atlantic seafront experiencing an average 10°C, the south-easterly Atlantic 22°C.
While still a maritime Mediterranean climate, the levels of rainfall in areas around Cape Town depend very much on position and /or altitude.
Climatically, the coastal strip between Cape Town and Walker Bay is similarly temperate. Grootbos Private Nature Reserve, sitting – at its highest point –at 520m, experiences 680mm of rain per annum, is coolest in July, hottest in February, with temperatures ranging between 14°C and 25°C.
The Cape Fold Belt, a mountainous range running from the Cedarberg Mountains in the northwest through to Port Elizabeth in the Eastern Cape, is as a rule wetter than Cape Town, with Table Mountain averaging 1400mm per annum, but again relatively dry wind currents flowing in off the western Atlantic mean that the Cedarberg Mountains are a lot drier than altitude would suggest, with average rainfalls of between 400mm and 700mm. Here temperatures in the summer can reach 40°C, while winter sees snow on some of the highest peaks. Spring and autumn (September and May) are the easiest seasons, with temperatures averaging out at around 25°C.
Located at latitude 27° - 34°, occupying an altitudinal range of between 300m*** to 1,300m, cooled by the south-easterly winds, and grown in well-drained soils, the Western Cape’s vineyards are – climatically speaking - perfectly positioned. Benefiting first from a generally temperate Mediterranean climate, the farming potential of the area is further bolstered by numerous microclimates, all of which provide Winelands localities with varying temperatures and levels of rainfall, which - when combined with the many soil types - makes for great variation of varietals.
All of which means that, in general, the Western Cape is best visited between September and May. September is when the fynbos (see accommodation Grootbos Private Nature Reserve) is at its most vibrant, while the dry summer makes for excellent hiking, site seeing and sampling wines on hotel and lodge terraces. September through to December is good for whale watching.
*A section of the Western Cape interior is semi-arid, experiencing along with the north-west and parts of the central plateau, a dry tropical climate.
**For logistic purposes the western Garden Route is included in The Eastern Cape and Garden Route
** *Some vineyards thrive at as low as 150m.