The Rock Surf Stats

The graph describes the range of swells directed at The Rock over a normal June. It is based on 3266 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about The Rock, and at The Rock the best grid node is 54 km away (34 miles). The rose diagram shows the distribution of swell directions and swell sizes, 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 5% of the time. Green and yellow show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens. The diagram indicates that the dominant swell direction, shown by the biggest spokes, was SSW, whereas the the dominant wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from The Rock and away from the coast. We lump these in 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 good for surfing at The Rock, 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 June, swells large enough to cause clean enough to surf waves at The Rock run for about 95% of the time.

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