Derrynane Surf Stats

The figure shows the range of swells directed at Derrynane through a typical October and is based upon 2976 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 optimum grid node based on what we know about Derrynane. In this particular case the best grid node is 31 km away (19 miles). The rose diagram describes the distribution of swell directions and swell sizes, 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 happened only 50% of the time. Green and yellow represent increasing swell sizes and red shows the biggest 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 prevailing swell direction, shown by the largest spokes, was SW (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 Derrynane 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 diagram. Because wind determines whether or not waves are clean enough to surf at Derrynane, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause surfable waves at Derrynane run for about 41% of the time.

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