Ponta Negra Surf Stats

The rose diagram shows the variation of swells directed at Ponta Negra over a normal May. It is based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Ponta Negra. In the case of Ponta Negra, the best grid node is 21 km away (13 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 13% of the time. Green and yellow show increasing swell sizes and red represents biggest swells greater than >3m (>10ft). 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 ENE, whereas the the prevailing wind blows from the SE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ponta Negra and away from the coast. 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 graph. Because wind determines whether or not waves are clean enough to surf at Ponta Negra, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause surfable waves at Ponta Negra run for about 87% of the time.

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