Portreath Harbour Wall Surf Stats

The figure shows the variation of swells directed at Portreath Harbour Wall through an average October. It is based on 3471 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 Portreath Harbour Wall. In this particular case the best grid node is 30 km away (19 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but 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 28% of the time. Green and yellow illustrate increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In either graph, 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 biggest spokes, was WNW, whereas the the prevailing wind blows from the SW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Portreath Harbour Wall and offshore. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Portreath Harbour Wall, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical October, swells large enough to cause surfable waves at Portreath Harbour Wall run for about 53% of the time.

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