Playa de San Cibrao Swell Statistics, September: All Swell – Any Wind
This image illustrates the range of swells directed at Playa de San Cibrao through an average September and is based upon 1920 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Playa de San Cibrao. In the case of Playa de San Cibrao, the best grid node is 33 km away (21 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing 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 19% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, 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 NW, 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 Playa de San Cibrao 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 plot. Because wind determines whether or not waves are surfable at Playa de San Cibrao, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause good for surfing waves at Playa de San Cibrao run for about 70% 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.