Nettley Bay Reefs Surf Stats

The graph shows the range of swells directed at Nettley Bay Reefs through a typical April, based on 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 most applicable grid node based on what we know about Nettley Bay Reefs. In this particular case the best grid node is 13 km away (8 miles). The rose diagram describes the distribution of swell sizes and swell direction, 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 occurred only 1.9% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was WSW (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Nettley Bay Reefs and away from the coast. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Nettley Bay Reefs, 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 Nettley Bay Reefs run for about 98% of the time.

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