Porth Beach Surf Stats

This picture shows the variation of swells directed at Porth Beach over a normal June, based on 3506 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the most applicable grid node based on what we know about Porth Beach. In the case of Porth Beach, the best grid node is 32 km away (20 miles). The rose diagram illustrates the distribution of swell sizes and directions, 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 13% of the time. Green and yellow represent increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the prevailing swell direction, shown by the largest spokes, was W (which was the same as the prevailing wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Porth Beach and out to sea. We lump these in 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 Porth Beach, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause surfable waves at Porth Beach run for about 44% of the time.

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