Waihau Bay Surf Stats

This image describes the combination of swells directed at Waihau Bay through an average October, based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the optimum grid node based on what we know about Waihau Bay. In the case of Waihau Bay, the best grid node is 15 km away (9 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without 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 63% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the prevailing swell direction, shown by the longest spokes, was N, whereas the the dominant wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Waihau Bay and away from the coast. We lump these in 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 surfable at Waihau Bay, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical October, swells large enough to cause good for surfing waves at Waihau Bay run for about 21% of the time.

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