Unawatuna Surf Stats

The graph describes the combination of swells directed at Unawatuna through an average June, based on 3384 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the most applicable grid node based on what we know about Unawatuna. In the case of Unawatuna, the best grid node is 27 km away (17 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 0.7% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the largest spokes, was SW, whereas the the dominant wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Unawatuna 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 plot. Because wind determines whether or not waves are good for surfing at Unawatuna, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause clean enough to surf waves at Unawatuna run for about 99% of the time.

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