Dunedin - St Clair Surf Stats

The figure illustrates the combination of swells directed at Dunedin - St Clair over a normal June, based on 3266 NWW3 model predictions since 2006 (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 Dunedin - St Clair. In this particular case the best grid node is 10 km away (6 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 24% of the time. Green and yellow show increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the dominant swell direction, shown by the biggest spokes, was S, whereas the the most common wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Dunedin - St Clair and offshore. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Dunedin - St Clair, 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 June, swells large enough to cause good for surfing waves at Dunedin - St Clair run for about 76% of the time.

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