St Simons Island Surf Stats

This picture shows the combination of swells directed at St Simons Island through a typical August, based on 3472 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 best grid node based on what we know about St Simons Island. In this particular case the best grid node is 39 km away (24 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 20% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either 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 largest spokes, was ESE, whereas the the prevailing wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from St Simons Island and out to sea. We group 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 clean enough to surf at St Simons Island, 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 August, swells large enough to cause surfable waves at St Simons Island run for about 80% of the time.

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