Porth Colmon Surf Stats

The graph shows the variation of swells directed at Porth Colmon over a normal July and is based upon 3720 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 Colmon. In the case of Porth Colmon, the best grid node is 18 km away (11 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without 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 occurred 55% of the time. Green and yellow illustrate increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the prevailing swell direction, shown by the longest spokes, was SW, whereas the the prevailing wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Porth Colmon 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 graph. Because wind determines whether or not waves are good for surfing at Porth Colmon, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause clean enough to surf waves at Porth Colmon run for about 2.0% of the time.

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