Porpoise Bay Surf Stats

The rose diagram shows the range of swells directed at Porpoise Bay through a typical September and is based upon 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the most applicable grid node based on what we know about Porpoise Bay. In this particular case the best grid node is 38 km away (24 miles). The rose diagram shows 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 happened only 9% of the time. Green and yellow represent increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the most common swell direction, shown by the largest spokes, was SSW, whereas the the prevailing wind blows from the NW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Porpoise Bay and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Porpoise Bay, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause clean enough to surf waves at Porpoise Bay run for about 91% of the time.

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