The Jetty Surf Stats

The rose diagram shows the range of swells directed at The Jetty over a normal July, based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the optimum grid node based on what we know about The Jetty. In this particular case the best grid node is 37 km away (23 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These occurred only 7% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the longest spokes, was SSE, whereas the the prevailing wind blows from the SW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from The Jetty and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at The Jetty, 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 July, swells large enough to cause surfable waves at The Jetty run for about 93% of the time.

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