Shelter Island Surf Stats

This chart shows the combination of swells directed at Shelter Island over a normal October and is based upon 3470 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about Shelter Island. In the case of Shelter Island, the best grid node is 28 km away (17 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 78% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest 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 prevailing swell direction, shown by the biggest spokes, was ENE (which was the same as the prevailing wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Shelter Island 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 plot. Because wind determines whether or not waves are surfable at Shelter Island, 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 October, swells large enough to cause good for surfing waves at Shelter Island run for about 1.0% of the time.

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