Porth Beach Surf Stats

This image shows the variation of swells directed at Porth Beach through an average November and is based upon 3347 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 Porth Beach. In the case of Porth Beach, the best grid node is 32 km away (20 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 12% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the dominant swell direction, shown by the biggest spokes, was W (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Porth Beach 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 diagram. Because wind determines whether or not waves are clean enough to surf at Porth Beach, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause surfable waves at Porth Beach run for about 72% of the time.

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