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Surf Break Rating

Rate Waihau Bay

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Waihau Bay Swell Statistics, March: All Swell – Any Wind

The figure shows the range of swells directed at Waihau Bay through an average March and is based upon 2716 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Waihau Bay. In this particular case the best grid node is 15 km away (9 miles).

The rose diagram describes the distribution of swell sizes and swell direction, 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 happened only 68% of the time. Green and yellow show increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell was forecast.

The diagram indicates that the dominant swell direction, shown by the longest spokes, was NNE, whereas the the prevailing wind blows from the ESE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Waihau Bay and out to sea. 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 surfable at Waihau Bay, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical March, swells large enough to cause good for surfing waves at Waihau Bay run for about 19% of the time.

IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.