Porthjoke Surf Stats

The graph describes the combination of swells directed at Porthjoke through an average July. It is based on 3720 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Porthjoke. In the case of Porthjoke, the best grid node is 28 km away (17 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, 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 occurred only 6% of the time. Green and yellow show increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. 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 largest spokes, was W (which was the same as the dominant wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Porthjoke and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Porthjoke, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause clean enough to surf waves at Porthjoke run for about 47% of the time.

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