Watamu Bay Surf Stats

The figure describes the variation of swells directed at Watamu Bay through an average July. It is based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the most applicable grid node based on what we know about Watamu Bay, and at Watamu Bay the best grid node is 17 km away (11 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 0.2% of the time. Green and yellow represent increasing swell sizes and red represents the highest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the longest spokes, was SE, whereas the the dominant wind blows from the S. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Watamu Bay 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 Watamu Bay, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause surfable waves at Watamu Bay run for about 100% of the time.

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