Alnes Lighthouse Surf Stats

The rose diagram shows the combination of swells directed at Alnes Lighthouse through an average August, based on 3574 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Alnes Lighthouse, and at Alnes Lighthouse the best grid node is 3 km away (2 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 19% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the most common swell direction, shown by the biggest spokes, was NW (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Alnes Lighthouse and away from the coast. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Alnes Lighthouse, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause surfable waves at Alnes Lighthouse run for about 22% of the time.

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