Southport Main Beach Surf Stats

The graph illustrates the combination of swells directed at Southport Main Beach through a typical September, based on 3360 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 best grid node based on what we know about Southport Main Beach, and at Southport Main Beach the best grid node is 7 km away (4 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 25% of the time. Green and yellow show increasing swell sizes and red shows largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the dominant swell direction, shown by the biggest spokes, was ESE, whereas the the most common wind blows from the NNE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Southport Main Beach and out to sea. We group these 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 good for surfing at Southport Main Beach, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause clean enough to surf waves at Southport Main Beach run for about 75% of the time.

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