Church Bay Surf Stats

The rose diagram illustrates the combination of swells directed at Church Bay through an average July, based on 2976 NWW3 model predictions since 2008 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Church Bay. In the case of Church Bay, the best grid node is 15 km away (9 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 81% of the time. Green and yellow illustrate increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the dominant swell direction, shown by the biggest spokes, was NW, whereas the the most common wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Church Bay and away from the coast. 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 clean enough to surf at Church Bay, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause surfable waves at Church Bay run for about 2.0% of the time.

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