Praia de Sao Marcos Surf Stats

The figure describes the variation of swells directed at Praia de Sao Marcos through a typical May. It is based on 3439 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the most applicable grid node based on what we know about Praia de Sao Marcos. In the case of Praia de Sao Marcos, the best grid node is 61 km away (38 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 94% of the time. Green and yellow illustrate increasing swell sizes and red represents highest swells greater than >3m (>10ft). In either graph, 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 longest spokes, was NE, whereas the the dominant wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Praia de Sao Marcos and away from the coast. We combine these 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 Praia de Sao Marcos, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause surfable waves at Praia de Sao Marcos run for about 6% of the time.

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