The month of May is here, April and May have
This chart from http://www.snow-forecast.com shows the expected 3-day coverage during the passage of the cold-front period between 2am on Fri 1st to 8am on Sat 2nd.
Precipitation will vary by location, from heavy (5-10cm+) in the SW&S-Cape, to much lighter (1-5cm) inland in the N-Cape, and eventually over parts of KZN.
It is worth understanding that snowfall timing and depth varies with location and elevation. Snow will first fall on the highest peaks (above the freezing-level) in the west, and later on lower peaks and slopes (and further east).
The snow will not melt immediately (since no rain is predicted), but gradually from the lowest elevations (in reverse order). Skies should also clear fairly rapidly, making for good viewing conditions.
The following 6-hourly charts show the freezing-level dropping sharply from west to east, as the front moves over.