Summerville Surf Stats

The rose diagram illustrates the range of swells directed at Summerville through a typical April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the optimum grid node based on what we know about Summerville. In this particular case the best grid node is 28 km away (17 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 33% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the largest spokes, was SE, whereas the the most common wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Summerville and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Summerville, 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 April, swells large enough to cause good for surfing waves at Summerville run for about 35% of the time.

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