Ponta Das Aranhas Surf Stats

This chart shows the combination of swells directed at Ponta Das Aranhas over a normal October. It is based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the most applicable grid node based on what we know about Ponta Das Aranhas, and at Ponta Das Aranhas the best grid node is 37 km away (23 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but 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 28% of the time. Green and yellow represent increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the dominant swell direction, shown by the largest spokes, was E, whereas the the prevailing wind blows from the ENE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Ponta Das Aranhas and offshore. We combine 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 good for surfing at Ponta Das Aranhas, 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 October, swells large enough to cause clean enough to surf waves at Ponta Das Aranhas run for about 72% of the time.

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