Derrynane Surf Stats

This chart illustrates the range of swells directed at Derrynane through a typical April and is based upon 2880 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast 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 illustrates the distribution of swell sizes and swell direction, 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 only 49% of the time. Green and yellow show increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the most common swell direction, shown by the longest spokes, was WSW (which was the same as the most common wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Derrynane and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Derrynane, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average April, swells large enough to cause clean enough to surf waves at Derrynane run for about 37% of the time.

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