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Johnshaven ratings
Quality on a good day: 4.0
Consistency of Surf: 2.0
Difficulty Level: 3.0
Crowds: 4.0

Overall: 3.5

See all 18 ratings

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Surf Report Feed

Johnshaven Swell Statistics, May: All Swell – Any Wind

The figure illustrates the variation of swells directed at Johnshaven over a normal May and is based upon 2696 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Johnshaven. In this particular case the best grid node is 31 km away (19 miles).

The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but 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 64% of the time. Green and yellow illustrate increasing swell sizes and red represents largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens.

The diagram indicates that the prevailing swell direction, shown by the longest spokes, was S (which was the same as the most common wind direction). 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 clean enough to surf at Johnshaven, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical May, swells large enough to cause surfable waves at Johnshaven run for about 8% of the time.

IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.