Castletown Surf Stats

This image shows the range of swells directed at Castletown through a typical June. It is based on 2871 NWW3 model predictions since 2008 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Castletown, and at Castletown the best grid node is 68 km away (42 miles). The rose diagram describes the distribution of swell sizes and swell direction, 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 61% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the most common swell direction, shown by the largest spokes, was SSW, whereas the the prevailing wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Castletown and away from the coast. We combine 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 Castletown, 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 June, swells large enough to cause good for surfing waves at Castletown run for about 12% of the time.

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