Rhosneigr Surf Stats

The rose diagram illustrates the variation of swells directed at Rhosneigr through a typical September. It is based on 3358 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about Rhosneigr, and at Rhosneigr the best grid node is 26 km away (16 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but 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 54% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was SW, whereas the the most common wind blows from the WSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Rhosneigr and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Rhosneigr, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause clean enough to surf waves at Rhosneigr run for about 46% of the time.

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