South Stradbroke Surf Stats

This picture shows the variation of swells directed at South Stradbroke through an average June. It is based on 3266 NWW3 model predictions since 2006 (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 South Stradbroke. In the case of South Stradbroke, the best grid node is 11 km away (7 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 14% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was ESE, whereas the the prevailing wind blows from the SSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from South Stradbroke 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 clean enough to surf at South Stradbroke, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause surfable waves at South Stradbroke run for about 86% of the time.

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