The South Jetty Surf Stats

This picture shows the combination of swells directed at The South Jetty through a typical July, based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the optimum grid node based on what we know about The South Jetty, and at The South Jetty the best grid node is 36 km away (22 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 7% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the prevailing 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 South 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 diagram. Because wind determines whether or not waves are good for surfing at The South Jetty, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause clean enough to surf waves at The South Jetty run for about 93% of the time.

read more