Thermopylae Surf Stats
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All swells
![](/graphs/statistics/Thermopylae.surf.statistics.april.gif)
![](/graphs/statistics/SW.animated.gif)
![](/graphs/statistics/SW.label.animated.gif)
The graph illustrates the combination of swells directed at Thermopylae through an average April, based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Thermopylae, and at Thermopylae the best grid node is 38 km away (24 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 4% of the time. Green and yellow represent increasing swell sizes and red shows largest 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 most common wind blows from the S. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Thermopylae and offshore. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Thermopylae, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause surfable waves at Thermopylae run for about 96% of the time.