Brant Rock Surf Stats

The rose diagram describes the combination of swells directed at Brant Rock through a typical May, based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Brant Rock. In the case of Brant Rock, the best grid node is 16 km away (10 miles). The rose diagram illustrates the distribution of swell sizes and directions, 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 happened 65% of the time. Green and yellow illustrate increasing swell sizes and red shows highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was ENE, whereas the the dominant wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Brant Rock and out to sea. 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 surfable at Brant Rock, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause good for surfing waves at Brant Rock run for about 35% of the time.

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