Ponta Negra Surf Stats

This chart describes the combination of swells directed at Ponta Negra through a typical July and is based upon 3720 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the optimum grid node based on what we know about Ponta Negra. In this particular case the best grid node is 21 km away (13 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 70% of the time. Green and yellow illustrate increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the prevailing swell direction, shown by the largest spokes, was E, whereas the the dominant wind blows from the SE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Ponta Negra and offshore. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing 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. Over an average July, swells large enough to cause clean enough to surf waves at Ponta Negra run for about 30% of the time.

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