St Marys Rivermouth Surf Stats

This picture illustrates the combination of swells directed at St Marys Rivermouth over a normal May. It is based on 3422 NWW3 model predictions since 2007 (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 St Marys Rivermouth, and at St Marys Rivermouth the best grid node is 47 km away (29 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 31% of the time. Green and yellow represent 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 happens. The diagram suggests that the dominant swell direction, shown by the biggest spokes, was E, whereas the the most common wind blows from the SE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from St Marys Rivermouth 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 plot. Because wind determines whether or not waves are surfable at St Marys Rivermouth, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause good for surfing waves at St Marys Rivermouth run for about 69% of the time.

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