Stillbaai Surf Stats

This image describes the combination of swells directed at Stillbaai over a normal June. It is based on 3266 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Stillbaai, and at 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 lacks 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 5% of the time. Green and yellow illustrate increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the dominant swell direction, shown by the largest spokes, was SSW, whereas the the dominant wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Stillbaai and away from the coast. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. 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. During a typical June, swells large enough to cause surfable waves at Stillbaai run for about 95% of the time.

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