According to the South African Weather Service, there will be a significant drop in daytime temperatures caused by a cut-off low.
“There is a cut-off low over the country and on the surface it is usually associated with a cold front which is what is happening now,” weather service forecaster Lulama Theme told the Pretoria News.
He explained that the air in South Africa generally moved from west to east.
But when the air was disturbed, a trough formed which could intensify into a low-pressure system.
When this pressure system gets cut off from the east to west flow, a cut-off low is formed, Theme said.
Pretoria would only experience the cold front tomorrow as the city was ahead of the cold front, he said.
“Friday (today) it will still be cool weather as we have been having all week, but there is a 60% chance of severe thunderstorms,” he warned.
This will be followed by the drastic drop in temperature on Saturday.
The cold front will have passed over the city by Sunday.
That means Pretoria residents should pull out the hot chocolate and heaters and prepare themselves for a minimum temperature of 9ºC and a high of 12ºC.
Sunday will bring a low of 9ºC and a maximum temperature of 16ºC.
Monday will again bring a low of 9ºC and a high of 18ºC, while the daytime temperatures will continue to rise slightly into the new week.
“While much of the country has enjoyed mild and sunny autumn weather of late, this is set to change fairly drastically over the majority of the country this weekend,” Kevin Rae, the weather service’s chief forecaster, said.
“The good news is that by Monday, we can look forward to a general recovery of daytime temperatures across the entire country."
"Then, many regions will experience sunny and mild weather,” Rae went on to say.
He said said the South African Weather Service would continue to monitor further developments during this period.
It would issue subsequent updates as they may be required, he added.