The figure illustrates the range of swells directed at Playa de San Lorenzo over a normal northern hemisphere autumn and is based upon 5144 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the best grid node based on what we know about Playa de San Lorenzo. In the case of Playa de San Lorenzo, the best grid node is 53 km away (33 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 11% of the time. Green and yellow represent increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In both graphs, 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 longest spokes, was NW, whereas the the most common wind blows from the NNE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Playa de San Lorenzo 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 diagram. Because wind determines whether or not waves are good for surfing at Playa de San Lorenzo, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical northern hemisphere autumn, swells large enough to cause clean enough to surf waves at Playa de San Lorenzo run for about 75% 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.