Katwijk aan Zee Surf Stats

The graph illustrates the variation of swells directed at Katwijk aan Zee over a normal October, based on 3468 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about Katwijk aan Zee. In the case of Katwijk aan Zee, the best grid node is 31 km away (19 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 were forecast 61% of the time. Green and yellow represent increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). 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 NW, whereas the the most common wind blows from the SSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Katwijk aan Zee and offshore. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Katwijk aan Zee, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical October, swells large enough to cause clean enough to surf waves at Katwijk aan Zee run for about 39% of the time.

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