Petit Sancho Surf Stats

The rose diagram shows the range of swells directed at Petit Sancho over a normal August. It is based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the optimum grid node based on what we know about Petit Sancho, and at Petit Sancho the best grid node is 47 km away (29 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These occurred only 31% of the time. Green and yellow show increasing swell sizes and red illustrates biggest 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 most common swell direction, shown by the biggest spokes, was S, whereas the the prevailing wind blows from the ESE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Petit Sancho 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 diagram. Because wind determines whether or not waves are good for surfing at Petit Sancho, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical August, swells large enough to cause clean enough to surf waves at Petit Sancho run for about 55% of the time.

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