JD Reef Surf Stats

The graph describes the combination of swells directed at JD Reef through an average August. It is based on 3582 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about JD Reef, and at JD Reef the best grid node is 26 km away (16 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 23% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was SSE, whereas the the dominant wind blows from the W. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from JD Reef and out to sea. We lump these in 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 JD Reef, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause clean enough to surf waves at JD Reef run for about 77% of the time.

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