Mangawhai Heads Surf Stats

The figure illustrates the range of swells directed at Mangawhai Heads through an average April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the most applicable grid node based on what we know about Mangawhai Heads, and at Mangawhai Heads the best grid node is 37 km away (23 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 22% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the dominant swell direction, shown by the longest spokes, was NE, whereas the the most common wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Mangawhai Heads and out to sea. 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 diagram. Because wind determines whether or not waves are surfable at Mangawhai Heads, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause good for surfing waves at Mangawhai Heads run for about 78% of the time.

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