Belle Ile Surf Stats

The figure shows the combination of swells directed at Belle Ile through an average April and is based upon 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the most applicable grid node based on what we know about Belle Ile. In this particular case the best grid node is 40 km away (25 miles). The rose diagram shows 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 45% of the time. Green and yellow show increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was W, whereas the the prevailing wind blows from the N. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Belle Ile and out to sea. 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 clean enough to surf at Belle Ile, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause surfable waves at Belle Ile run for about 55% of the time.

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