Kahalu'u Surf Stats

This image describes the range of swells directed at Kahalu'u over a normal June, based on 3506 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 best grid node based on what we know about Kahalu'u. In the case of Kahalu'u, the best grid node is 10 km away (6 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 83% of the time. Green and yellow illustrate increasing swell sizes and highest 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 occurs. The diagram indicates that the dominant swell direction, shown by the biggest spokes, was WSW, whereas the the dominant wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Kahalu'u and offshore. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Kahalu'u, 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 June, swells large enough to cause clean enough to surf waves at Kahalu'u run for about 17% of the time.

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