Kahuku Ranch Surf Stats

The rose diagram illustrates the combination of swells directed at Kahuku Ranch through an average July, based on 3720 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Kahuku Ranch, and at Kahuku Ranch the best grid node is 22 km away (14 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 75% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In both graphs, 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 longest spokes, was SSW, whereas the the most common wind blows from the ENE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Kahuku Ranch and offshore. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Kahuku Ranch, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause clean enough to surf waves at Kahuku Ranch run for about 25% of the time.

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