Kosi Bay Surf Stats

This picture illustrates the combination of swells directed at Kosi Bay through an average November, based on 3347 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 Kosi Bay. In this particular case the best grid node is 18 km away (11 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 17% of the time. Green and yellow represent increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the largest spokes, was SE, whereas the the most common wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Kosi Bay and offshore. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Kosi Bay, 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 November, swells large enough to cause clean enough to surf waves at Kosi Bay run for about 83% of the time.

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