Porth Ceriad Surf Stats

This image illustrates the variation of swells directed at Porth Ceriad through a typical April, based on 3360 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 best grid node based on what we know about Porth Ceriad. In this particular case the best grid node is 33 km away (21 miles). The rose diagram describes the distribution of swell sizes and swell direction, 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 were forecast 58% of the time. Green and yellow represent increasing swell sizes and red represents largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the most common swell direction, shown by the largest spokes, was SW (which was the same as the most common wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Porth Ceriad and away from the coast. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Porth Ceriad, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average April, swells large enough to cause surfable waves at Porth Ceriad run for about 42% of the time.

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