Donut Island Surf Stats

The figure describes the variation of swells directed at Donut Island over a normal May and is based upon 2838 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Donut Island. In this particular case the best grid node is 26 km away (16 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without 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 occurred 51% of the time. Green and yellow show increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the dominant swell direction, shown by the largest spokes, was NE, whereas the the dominant wind blows from the WSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Donut Island and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Donut Island, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause good for surfing waves at Donut Island run for about 49% of the time.

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