Extremely hot and unconformable conditions are expected to continue into Thursday, the 26th December, over the Northern Cape.
The SA Weather Service (SAWS) said conditions are expected to reach upper 30s and 40°.
As a result, residents are advised to take necessary precaution against hyperthermia, heat strokes and other related health risks.
Severe thunderstorms are also expected over Beaufort West, Khai-Ma, Hantham (East of Calvinia), Karoo Hoogland (East of Sutherland).
Rain is expected to follow thereafter, along with lightning and damaging wind.
Similar conditions are also expected to continue into Thursday, over parts of the Free State and the North West.
SAWS said a surface trough may bring along thunderstorms and gusts to the following districts in the Eastern Cape: Joe Gqabi, Chris Hani, OR Tambo, Alfred Nzo, Amathole, Dr Beyer’s Naude, Blue Crane Route, Makana, Buffalo City and Ndlambe.