Ko Samui Surf Stats

This chart illustrates the range of swells directed at Ko Samui through a typical April, based on 3353 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and 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 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 70% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the largest spokes, was ESE, whereas the the most common wind blows from the SSE. 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 combine 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 clean enough to surf 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. Over an average April, swells large enough to cause surfable waves at Ko Samui run for about 30% of the time.

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