This chart illustrates the range of swells directed at Praia Brava through an average southern hemisphere summer and is based upon 5048 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Praia Brava, and at Praia Brava the best grid node is 22 km away (14 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 43% of the time. Green and yellow illustrate increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the most common swell direction, shown by the biggest spokes, was E, whereas the the most common wind blows from the NE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Praia Brava and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Praia Brava, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical southern hemisphere summer, swells large enough to cause surfable waves at Praia Brava run for about 24% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.