Mahai'ula Bay Surf Stats

This image illustrates the combination of swells directed at Mahai'ula Bay over a normal August. It is based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable grid node based on what we know about Mahai'ula Bay. In the case of Mahai'ula Bay, the best grid node is 24 km away (15 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 83% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the most common swell direction, shown by the biggest spokes, was WSW, whereas the the most common wind blows from the NNE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Mahai'ula Bay and away from the coast. We combine 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 clean enough to surf at Mahai'ula Bay, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical August, swells large enough to cause surfable waves at Mahai'ula Bay run for about 1.0% of the time.

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