St Brelade's Bay Surf Stats

This picture illustrates the range of swells directed at St Brelade's Bay through an average April and is based upon 3352 NWW3 model predictions since 2007 (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 St Brelade's Bay, and at St Brelade's Bay the best grid node is 25 km away (16 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing 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 72% of the time. Green and yellow represent increasing swell sizes and red illustrates largest 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 WSW, whereas the the most common wind blows from the N. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from St Brelade's Bay and away from the coast. We group 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 St Brelade's Bay, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause surfable waves at St Brelade's Bay run for about 7% of the time.

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