Port Geographe Bay Surf Stats

The graph describes the range of swells directed at Port Geographe Bay over a normal April and is based upon 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 optimum grid node based on what we know about Port Geographe Bay, and at Port Geographe Bay the best grid node is 36 km away (22 miles). The rose diagram describes the distribution of swell sizes and swell direction, 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 93% of the time. Green and yellow show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was W, whereas the the dominant wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Port Geographe Bay and out to sea. We group these 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 clean enough to surf at Port Geographe Bay, 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 April, swells large enough to cause surfable waves at Port Geographe Bay run for about 4% of the time.

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