CAPE TOWN - The heatwave is reaching its peak on Thursday with Vredendal expected to be hottest with a high of 46ºC and Cape Town reaching 39ºC.
Similar temperatures will also affect the Cape Winelands, West Coast District and the western interior of the Northern Cape.
For a period of hot weather to be considered a heatwave, the unusual heat must persist for three days or more over the same area.
In this case, the high heat began on Wednesday for the areas near the west coast and continues until Friday.
Although Friday will be slightly cooler, it will still be hot enough over these areas to be considered a heatwave.
This changes over the weekend as milder weather is expected, but the region remains dry.
In addition to a normal summertime circulation pattern settling over South Africa, a strong high pressure in the upper atmosphere is causing stable, stagnant conditions over the western parts.
The same system also enhances heating and results in a sharp spike in temperatures.