Cape Mendocino Surf Stats

The rose diagram describes the range of swells directed at Cape Mendocino through an average June. It is based on 3506 NWW3 model predictions since 2006 (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 Cape Mendocino. In this particular case the best grid node is 13 km away (8 miles). The rose diagram describes the distribution of swell sizes and swell direction, 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 only 69% of the time. Green and yellow show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the dominant swell direction, shown by the longest spokes, was SW, whereas the the dominant wind blows from the NNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Cape Mendocino and away from the coast. 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 clean enough to surf at Cape Mendocino, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause surfable waves at Cape Mendocino run for about 31% of the time.

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