The South African Weather Service issued the warning for heavy thunderstorms, hail, localised flooding and damaging winds and said these conditions could last up until 11pm this evening.
Forecaster Jan Vermeulen said that they spotted the storm brewing on the radar and issued the warning.
“The storms in Johannesburg seem to be abating now, there has been confirmed hail in parts Pretoria, Cullinan and is expected to reach Hartebeespoort and the west of Pretoria as well,” said Vermeulen.
The size of the hail is because the clouds are very high and droplets get taken up by updrafts, form into ice and then get taken up again, this process continues whilst the hailstones build in size until they are so heavy the clouds can no longer hold them.
Users on twitter reported the massive storm hitting everywhere from Roodepoort on the West Rand to Menlyn in Pretoria, with many sharing images of hail stones the size of apples and gold balls.