Ilha Surf Stats

The figure describes the variation of swells directed at Ilha through an average August, based on 3582 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about Ilha. In this particular case the best grid node is 22 km away (14 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 1.2% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was SE, whereas the the dominant wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Ilha and offshore. We lump these in 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 Ilha, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause surfable waves at Ilha run for about 99% of the time.

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