Nantasket Beach Surf Stats

The figure illustrates the combination of swells directed at Nantasket Beach through a typical June and is based upon 2786 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 most applicable grid node based on what we know about Nantasket Beach. In the case of Nantasket Beach, the best grid node is 38 km away (24 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 73% of the time. Green and yellow illustrate increasing swell sizes and red shows largest 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 most common swell direction, shown by the largest spokes, was ENE, whereas the the most common wind blows from the SSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Nantasket Beach and away from the coast. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Nantasket Beach, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average June, swells large enough to cause good for surfing waves at Nantasket Beach run for about 27% of the time.

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