Collaroy Surf Stats

This chart describes the combination of swells directed at Collaroy through a typical August and is based upon 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about Collaroy. In the case of Collaroy, the best grid node is 31 km away (19 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without 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 79% of the time. Green and yellow represent increasing swell sizes and red shows highest 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 dominant swell direction, shown by the largest spokes, was ENE, whereas the the dominant wind blows from the W. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Collaroy and offshore. 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 diagram. Because wind determines whether or not waves are clean enough to surf at Collaroy, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average August, swells large enough to cause surfable waves at Collaroy run for about 7% of the time.

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