Southern hemisphere heat waves are back, and the South African Weather Service has issued a heat wave warning for the northeastern provinces of Gauteng (which includes Johannesburg and Pretoria), Mpumalanga and Limpopo, which contains the Kruger National Park.

Weather forecaster, Vanepia Phakula, said the warning was expected to continue through to this weekend.

At the spring equinox, temperatures were around average, but soon afterwards the thermometer soared. Pretoria has an average maximum temperature of 29C for October, but since the start of the month it has been above that. Temperatures have reached 37C over the last two days.

Skukuza, on the edge of Kruger National Park hit 42C on Monday; it too should expect temperatures to be around 29C.

The heat is drifting slowly south, and KwaZulu-Natal is next in line.

Pietermaritzburg, in KwaZulu-Natal, is in the midst of the driest year in a century. The city is forecast to approach the 40C mark in the next two days.

As temperatures reach into the 40s in Pietermaritzburg, Newcastle, Ulundi and Ladysmith, the Weather Service and Umgeni Water have urged people to conserve water, and prepare for a dry summer.

"Currently there is a very strong El Nino phase in effect, and there is significant concern for South Africa's summer rainfall areas. The coming summer is unlikely to provide much relief for current drought-stricken areas such as KwaZulu-Natal."

A recent report by the Council for Scientific and Industrial Research (CSIR) said that 2015 may be the warmest year ever recorded in Africa.

According to the CSIR this is partly due to climate change, and partly due to the El Nino event currently taking place in the Pacific Ocean.

Temperatures over subtropical southern Africa have risen at more than twice the global rate over the last five decades. It is therefore likely that there will be further heat waves across the continent, and South Africa will be not be the only country affected.

Source: Al Jazeera and agencies