That entirely depends on where in SA you are going.
Around the Kruger Park in the NE of the country it is in a tropical river delta region, so yes is the answer.
If you are going to West and East Cape, then it is unnecessary.
South Africa has a rule that you must have two adjacent blank pages in your passport when you arrive.
Having said that when I went there they used the single blank page opposite my photo, so it may be one of those things thaey enforce when they feel like it.