Number Fours Surf Stats

The graph describes the variation of swells directed at Number Fours over a normal September. It is based on 2880 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Number Fours, and at Number Fours the best grid node is 35 km away (22 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 occurred only 48% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the longest spokes, was S, whereas the the dominant wind blows from the ENE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Number Fours and out to sea. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Number Fours, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical September, swells large enough to cause good for surfing waves at Number Fours run for about 52% of the time.

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