Lyall Bay Surf Stats

The graph describes the range of swells directed at Lyall Bay through a typical September. It is based on 3358 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Lyall Bay. In the case of Lyall Bay, the best grid node is 31 km away (19 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks 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 happened only 42% of the time. Green and yellow illustrate increasing swell sizes and red represents the highest swells, greater than >3m (>10ft). In either graph, 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 biggest spokes, was S, whereas the the dominant wind blows from the NW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Lyall Bay and offshore. We group these 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 surfable at Lyall Bay, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause good for surfing waves at Lyall Bay run for about 34% of the time.

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