Manly-South Steyne Surf Stats

This image describes the variation of swells directed at Manly-South Steyne through a typical October. It is based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the best grid node based on what we know about Manly-South Steyne, and at Manly-South Steyne the best grid node is 29 km away (18 miles). The rose diagram describes the distribution of swell sizes and directions, 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 37% of the time. Green and yellow represent increasing swell sizes and highest 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 was forecast. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was SSE, whereas the the dominant wind blows from the ENE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Manly-South Steyne and away from the coast. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Manly-South Steyne, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause clean enough to surf waves at Manly-South Steyne run for about 19% of the time.

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