Forecaster Puseletso Mofokeng said temperatures were between 35 and 40 degrees in some parts of the Free State, the Northern Cape, North West, Limpopo, Mpumalanga and Gauteng.

While many areas were experiencing high temperatures, not all of them were in the "heatwave category".

Mofokeng said: "We look at the hottest month of the year, January, and find an average value of the highest temperature. A heatwave occurs when we record temperatures five degrees higher than the normal temperature for three consecutive days."

The heatwave was expected to last until Monday, with some rain at the weekend.

"There's a 60% chance of rain over Gauteng this evening," he said.

"Scattered showers are also forecast on Saturday and Sunday for KwaZulu-Natal, Free State, the North West, Limpopo and Mpumalanga."