Statistiques de Surf de Portreath Harbour Wall

This chart illustrates the variation of swells directed at Portreath Harbour Wall through a typical August. It is based on 3590 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Portreath Harbour Wall, and at Portreath Harbour Wall the best grid node is 30 km away (19 miles). The rose diagram describes 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 only 16% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest 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 WNW, whereas the the most common wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Portreath Harbour Wall and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Portreath Harbour Wall, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average August, swells large enough to cause good for surfing waves at Portreath Harbour Wall run for about 46% of the time.

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