Please be aware that Johannesburg has multiple airports and that these results are for all airports serving the city.
The best month to fly between Johannesburg and Cape Town is June and the most expensive month to fly is December. (Average prices, based on 734 datapoints.)
The best day to arrive at Johannesburg is Saturday and it would be best to avoid Friday, as prices are on average 74.09% higher than on Saturday. (Average prices, based on 366 datapoints.)