Herangi Beach Surf Stats

The rose diagram shows the variation of swells directed at Herangi Beach through a typical May, based on 3440 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the best grid node based on what we know about Herangi Beach, and at Herangi Beach the best grid node is 17 km away (11 miles). The rose diagram describes the distribution of swell sizes and directions, 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 occurred only 94% of the time. Green and yellow show increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the most common swell direction, shown by the longest spokes, was NW, whereas the the prevailing wind blows from the SW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Herangi Beach and out to sea. 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 clean enough to surf at Herangi Beach, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause surfable waves at Herangi Beach run for about 6% of the time.

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