Residents of Johannesburg have been warned to take extra precautions, as heavy rainfall could result in localised flooding.
Emergency Services spokesperson Robert Mulaudzi said that the country had "officially entered into thunderstorm season".
He warned residents in low lying areas, especially those in informal settlements, "to move to higher ground when there is a need to do so".
"Following the past incidents, which left a number of roads flooded, vehicles being swept away by strong floods, houses and vehicles were damaged in most parts of the city, we call on our residents and motorists to take necessary safety precautions."
Mulaudzi said the City's disaster management and emergency services were on high alert, mostly at the 189 low lying informal settlements.
"[The] disaster management centre is fully operational and monitoring teams have been dispatched to all seven regions of the city to make sure that we can respond to any emergency which might occur as quickly as possible."
According to the SA Weather Service, heavy rains on Thursday and Friday could result in localised flooding in parts of KwaZulu-Natal and Gauteng.
Forecaster Victoria Nurse told News24 that there would be a weather system moving eastward.
"We could get localised flooding, depending on the amount of rainfall."
She said that there was also a warning for heavy rainfall over the southern and central parts of KwaZulu-Natal for Thursday.
"We are monitoring the situation," she said.