Cotton Tree Surf Stats

The rose diagram illustrates the variation of swells directed at Cotton Tree through an average September. It is based on 3360 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 best grid node based on what we know about Cotton Tree, and at Cotton Tree the best grid node is 31 km away (19 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 0% of the time. Green and yellow show increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the most common swell direction, shown by the biggest spokes, was S, whereas the the most common wind blows from the SW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Cotton Tree and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Cotton Tree, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause clean enough to surf waves at Cotton Tree run for about 100% of the time.

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