St Jean de Monts Surf Stats

This image shows the combination of swells directed at St Jean de Monts over a normal November and is based upon 3347 NWW3 model predictions since 2006 (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 St Jean de Monts. In this particular case the best grid node is 31 km away (19 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 9% of the time. Green and yellow show increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, 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 (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 St Jean de Monts and out to sea. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at St Jean de Monts, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause surfable waves at St Jean de Monts run for about 91% of the time.

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