Hartley Reef Surf Stats

This picture shows the combination of swells directed at Hartley Reef over a normal July. It is based on 3224 NWW3 model predictions since 2008 (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 Hartley Reef, and at Hartley Reef the best grid node is 30 km away (19 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened 57% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was NNE, 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 Hartley Reef and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Hartley Reef, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause clean enough to surf waves at Hartley Reef run for about 9% of the time.

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