San Miguel - Areias Swell Statistics, May: All Swell – Any Wind
The figure illustrates the range of swells directed at San Miguel - Areias through a typical May and is based upon 2200 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about San Miguel - Areias. In this particular case the best grid node is 21 km away (13 miles).
The rose diagram describes the distribution of swell sizes and swell direction, 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 happened only 29% of the time. Green and yellow illustrate increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the biggest spokes, was NNW (which was the same as the most common wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from San Miguel - Areias and out to sea. 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 San Miguel - Areias, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause good for surfing waves at San Miguel - Areias run for about 59% 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.