THE CAPE CLIMATE
Table Mountain and the mountains of the south-western Cape have a Mediterranean climate, enjoying long warm and dry summers and a cool and wet but relatively short winter.
The November – March summer months are often hot and windy – sometimes extremely so – but hikers are more or less guaranteed dry weather. The wind and temperatures drop during the April and May autumn months, often seen as the best time for hiking in the Cape.
The winter rains of June through August needn’t put off hikers completely: in between rain storms there are long periods of mild and sunny weather – simply perfect for hiking. Temperatures increase in the September and October spring months as the fynbos comes into full flower.
Seventy per cent of the region’s rainfall occurs from June through September, mostly in the form of stormy cold fronts driven in from the north-west Atlantic bearing heavy rain and strong winds. There is occasional rain in October and November; December through March is a very dry period with virtually no rain.
The rain is however unevenly dispersed. The mountains of the south-western Cape receive an average of 1 000mm (40 inches) of rain a year, making them far wetter than the lower areas of the region which average between 250 and 650mm. However, rainfall is affected by the aspect of the mountains – the way they face – and Table Mountain provides a good example.
The eastern slopes of Table Mountain (those above Kirstenbosch Gardens and Constantia) receive more than four times the rain experienced on the drier western slopes (above Camps Bay). The reason is summer’s prevailing wind, a strong south-easterly wind which picks up moisture as it passes over False Bay. Condensing into clouds as it encounters Table Mountain’s eastern slopes, the “south-easter” forms the famous Table Cloth, the billowing white cloud that often sits on Table Mountain’s flat top – wonderful to look at; cold and soggy to be in.
Cape Town’s maritime climate means there is only a 10% difference between summer and winter temperatures. The south-western Cape records a range of 7 to 15°C in July and 15 to 25°C in January.
Hot spells do occur in summer when the temperature can reach over 40°C but generally speaking the cooling south-easterly winds keep the summer mercury down while the warming influence of two oceans means winters are never that cold. Table Mountain and the Cape Peninsula are largely free of frost although the mountains of the Cape winelands may have a coating of snow in winter.
Wind is an unavoidable fact of life in the south-western Cape; 20% of Cape Town’s November to April summer season is a gale force wind and at Cape Point it’s even more. The tip of the peninsula records 100 days of gale force wind a year – the average wind speed at Cape Point is 30kmh. In winter, cold fronts produce strong winds too but these are – unlike summer’s dry south-easters – full of rain.
The wind however serves a vital role: known locally as the Cape Doctor, the south-easter blows away summer’s soot and smog, clearing the air and revitalising the city. It also has a crucial ecological role: the wind-driven Table Cloth is responsible for 25% of Table Mountain’s annual rainfall – without it, few plants and animals could survive summer’s desiccating drought.