China Beach Surf Stats

This chart illustrates the variation of swells directed at China Beach through an average September. It is based on 3359 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about China Beach, and at China Beach the best grid node is 23 km away (14 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 48% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the most common swell direction, shown by the biggest spokes, was NE, whereas the the most common wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from China Beach and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at China Beach, 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 September, swells large enough to cause clean enough to surf waves at China Beach run for about 52% of the time.

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