Watamu Bay Surf Stats

The rose diagram illustrates the variation of swells directed at Watamu Bay through a typical May, based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Watamu Bay. In this particular case the best grid node is 17 km away (11 miles). The rose diagram illustrates 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 happened only 0.5% of the time. Green and yellow illustrate increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, 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 SE, whereas the the most common wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Watamu Bay and out to sea. 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 surfable at Watamu Bay, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause good for surfing waves at Watamu Bay run for about 100% of the time.

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