Withernsea Surf Stats

The figure shows the combination of swells directed at Withernsea over a normal April. It is based on 1200 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the best grid node based on what we know about Withernsea, and at Withernsea the best grid node is 31 km away (19 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 76% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the most common swell direction, shown by the longest spokes, was N, whereas the the prevailing 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 Withernsea and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Withernsea, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause good for surfing waves at Withernsea run for about 6% of the time.

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