Stellenbosch is half an hour's drive from Cape Town and it will take about 45minutes max to just about any crag in that area. Hellfire and Paarl Rock both are also 30mins or less away; Kleinmond 45min, so you've got a wide choice of trad, sport and bouldering in less than an hour in just about any direction.
March usually has awesome conditions for climbing, since the south easter (the cause of the schlauk) usually willl have died down by that time.
You still get hot days, but much milder than February. Just find a route in the shade and you're well away. Check out the guidebooks Western Cape Rock, Hellfire and Paarl Rocks.