Bay of Plenty Surf Stats

The figure shows the combination of swells directed at Bay of Plenty over a normal November. It is based on 3347 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about Bay of Plenty. In the case of Bay of Plenty, the best grid node is 20 km away (12 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 1.9% of the time. Green and yellow show increasing swell sizes and red represents the 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 prevailing swell direction, shown by the biggest spokes, was SW, 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 Bay of Plenty 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 Bay of Plenty, 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 November, swells large enough to cause clean enough to surf waves at Bay of Plenty run for about 98% of the time.

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