Marion Bay Surf Stats

The figure describes the variation of swells directed at Marion Bay through an average November. It is based on 1200 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the best grid node based on what we know about Marion Bay, and at Marion Bay the best grid node is 25 km away (16 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing 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 occurred only 80% of the time. Green and yellow show increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the most common swell direction, shown by the largest spokes, was E, whereas the the dominant wind blows from the WSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Marion Bay and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Marion Bay, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause good for surfing waves at Marion Bay run for about 20% of the time.

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