Ko Samui Surf Stats

The rose diagram illustrates the variation of swells directed at Ko Samui over a normal November and is based upon 3347 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Ko Samui, and at Ko Samui the best grid node is 49 km away (30 miles). The rose diagram shows the distribution of swell sizes and swell direction, 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 happened 57% of the time. Green and yellow show increasing swell sizes and red represents largest 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 dominant swell direction, shown by the longest spokes, was E, whereas the the most common wind blows from the ENE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ko Samui and away from the coast. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Ko Samui, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause clean enough to surf waves at Ko Samui run for about 43% of the time.

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