It was not polar air, it was just a normal cold front. While Gauteng and other provinces were still shivering from the cold, forecaster Edward Engelbrecht said the cold front had passed.
“It’s highly normal to get this type of weather in winter. We just haven’t had this cold a winter in two to three years. That’s probably why people think it’s so extreme, but it’s entirely normal,” Engelbrecht said.
He said social media posts suggesting polar air was responsible were sensationalising things.
“It’s definitely not polar air. It might have been subpolar air, but not polar air,” Engelbrecht said.
He said the polar air was too concentrated around the polar regions to reach South Africa.
“You get polar air by the 60-degree latitudes and here it’s about 35 to 25 degrees latitude,” he said.
He said there was a big area of high pressure behind the cold front which brought the cold air into the country.
Engelbrecht added neither La Nina nor El Nina had anything to do with the cold. He said in some years the cold fronts move more north or south than usual.
“So, in the past few years, the cold front didn’t move very far up north to really affect South Africa as it did this year,” he said.
Engelbrecht said a cold front is the boundary between warm or cool air and much colder air behind it.
“So the front is where the cold air meets the warm air,” he said.
Engelbrecht said a cold front takes about a day to move over the country, but the effects of cold air from it remain for about a week.
“Yes, it’s cold at the moment but the front has already passed,” Engelbrecht added.
He said often ahead of cold fronts, it was a bit warmer, especially along coastal regions, typically accompanied by northwesterly winds.
“As soon as a cold front enters, we get southwesterly winds which bring in the cold air from the oceans,” he said.
Engelbrecht said warm fronts develop in what they call mid-latitudes and will affect regions such as Marion Island in the Subantarctic Indian Ocean south of South Africa.