St Marys Rivermouth Surf Stats

This chart shows the combination of swells directed at St Marys Rivermouth through a typical September, based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the best grid node based on what we know about St Marys Rivermouth. In the case of St Marys Rivermouth, the best grid node is 47 km away (29 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 14% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the dominant swell direction, shown by the largest spokes, was E (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from St Marys Rivermouth and away from the coast. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at St Marys Rivermouth, 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 September, swells large enough to cause surfable waves at St Marys Rivermouth run for about 86% of the time.

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