Lyall Bay Surf Stats

The rose diagram shows the combination of swells directed at Lyall Bay through an average April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable 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 illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 35% of the time. Green and yellow illustrate increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). 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 S, whereas the the prevailing wind blows from the N. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Lyall Bay and offshore. 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 good for surfing at Lyall Bay, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause clean enough to surf waves at Lyall Bay run for about 36% of the time.

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