Kahalu'u Beach Park Surf Stats

This image illustrates the variation of swells directed at Kahalu'u Beach Park through an average 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 coast so we have chosen the optimum grid node based on what we know about Kahalu'u Beach Park. In the case of Kahalu'u Beach Park, the best grid node is 9 km away (6 miles). The rose diagram describes 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 10% of the time. Green and yellow show increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was SSW, whereas the the most common 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 Beach Park and offshore. We combine 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 surfable at Kahalu'u Beach Park, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause good for surfing waves at Kahalu'u Beach Park run for about 90% of the time.

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