Porth Nobla Surf Stats

The rose diagram shows the variation of swells directed at Porth Nobla through an average April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Porth Nobla. In the case of Porth Nobla, the best grid node is 26 km away (16 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast 68% of the time. Green and yellow illustrate increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the dominant swell direction, shown by the longest spokes, was SW, whereas the the prevailing wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Porth Nobla and out to sea. We lump these in 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 Porth Nobla, 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 April, swells large enough to cause clean enough to surf waves at Porth Nobla run for about 32% of the time.

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