Khao Lak / Nang Thong Surf Stats

The figure illustrates the variation of swells directed at Khao Lak / Nang Thong through a typical September, based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about Khao Lak / Nang Thong. In the case of Khao Lak / Nang Thong, 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 but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened 9% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the prevailing swell direction, shown by the largest spokes, was WSW, whereas the the most common wind blows from the W. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Khao Lak / Nang Thong and offshore. 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 clean enough to surf at Khao Lak / Nang Thong, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause surfable waves at Khao Lak / Nang Thong run for about 91% of the time.

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