Stillbaai Surf Stats

The figure illustrates the combination of swells directed at Stillbaai through an average October. It is based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about Stillbaai. In the case of Stillbaai, the best grid node is 15 km away (9 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 17% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the most common swell direction, shown by the largest spokes, was SSW, whereas the the most common wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Stillbaai and out to sea. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Stillbaai, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical October, swells large enough to cause surfable waves at Stillbaai run for about 83% of the time.

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