Caerfai Bay Surf Stats

The rose diagram illustrates the variation of swells directed at Caerfai Bay through an average September. It is based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Caerfai Bay. In this particular case the best grid node is 22 km away (14 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks 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 32% of the time. Green and yellow show increasing swell sizes and red represents largest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the prevailing swell direction, shown by the longest spokes, was WSW (which was the same as the most common wind direction). Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Caerfai Bay and offshore. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Caerfai Bay, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause surfable waves at Caerfai Bay run for about 34% of the time.

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