The majority of South Africa is a malaria free zone. Only as you head further north does it get a little sketch and if you are heading that side for safaris etc, you should double check with the reserve you are staying at prior to arrival. Eastern Cape (where we are having the wedding) is a Malaria free zone so no worries whilst traveling in the area. Only tequila shots necessary...
March / April is a great time of year in South Africa. Not too hot, not too humid and just cool enough in the evenings for a jumper. January is mid summer so the temperatures are gradually decreasing but here is a guide for what to pack:
Cape Town and Port Elizabeth have very similar climates with temperatures ranging from 60*F to 78*F. Kenton on Sea is known for random weather throughout the year so make sure you bring a raincoat or brollie. Johannesburg can get a little chillier in the mornings and evenings with lows around 55*F.
Cape Town: Average temp 60*F - 78*F
Johannesburg: Average temp 55*F - 75*F
Port Elizabeth/Kenton on Sea: Average temp 62*F - 75*F