Dunedin - St Kilda Beach Surf Stats

The figure shows the range of swells directed at Dunedin - St Kilda Beach over a normal May. It is based on 3422 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable grid node based on what we know about Dunedin - St Kilda Beach. In the case of Dunedin - St Kilda Beach, the best grid node is 10 km away (6 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 30% of the time. Green and yellow represent increasing swell sizes and red illustrates 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 longest spokes, was S, whereas the the prevailing wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Dunedin - St Kilda Beach and away from the coast. 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 graph. Because wind determines whether or not waves are good for surfing at Dunedin - St Kilda Beach, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause clean enough to surf waves at Dunedin - St Kilda Beach run for about 70% of the time.

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