Kahalu'u Beach Park Surf Stats

The rose diagram shows the range of swells directed at Kahalu'u Beach Park over a normal August and is based upon 3582 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Kahalu'u Beach Park. In this particular case the best grid node is 9 km away (6 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 13% of the time. Green and yellow represent increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the dominant swell direction, shown by the longest spokes, was SSW, 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 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 good for surfing at Kahalu'u Beach Park, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical August, swells large enough to cause clean enough to surf waves at Kahalu'u Beach Park run for about 87% of the time.

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