Yokohama Bay Surf Stats

The graph illustrates the combination of swells directed at Yokohama Bay through an average August, based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Yokohama Bay. In this particular case the best grid node is 27 km away (17 miles). The rose diagram shows the distribution of swell directions and swell sizes, 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 only 93% of the time. Green and yellow illustrate increasing swell sizes and red shows largest swells greater than >3m (>10ft). In each graph, 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 biggest spokes, was WNW, whereas the the most common wind blows from the ENE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Yokohama Bay and offshore. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Yokohama Bay, 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 August, swells large enough to cause surfable waves at Yokohama Bay run for about 7% of the time.

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