Johnshaven Surf Stats

This chart illustrates the range of swells directed at Johnshaven over a normal October, based on 3471 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 Johnshaven. In the case of Johnshaven, the best grid node is 31 km away (19 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 59% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, 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 S, whereas the the most common wind blows from the SW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Johnshaven and out to sea. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Johnshaven, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical October, swells large enough to cause clean enough to surf waves at Johnshaven run for about 20% of the time.

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