Old Kona Airport State Park Surf Stats

The rose diagram shows the combination of swells directed at Old Kona Airport State Park through an average June and is based upon 2786 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 best grid node based on what we know about Old Kona Airport State Park. In this particular case the best grid node is 17 km away (11 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, 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 happened only 94% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the prevailing swell direction, shown by the largest spokes, was W, whereas the the prevailing wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Old Kona Airport State Park 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 plot. Because wind determines whether or not waves are surfable at Old Kona Airport State Park, you can select a similar diagram 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 good for surfing waves at Old Kona Airport State Park run for about 1.0% of the time.

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