Kanaha Swell Statistics, October: All Swell – Any Wind
The graph describes the range of swells directed at Kanaha through a typical October, based on 1984 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 most applicable grid node based on what we know about Kanaha. In this particular case the best grid node is 15 km away (9 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, 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 27% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the dominant swell direction, shown by the longest spokes, was NNE, whereas the the dominant wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Kanaha and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Kanaha, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average October, swells large enough to cause good for surfing waves at Kanaha run for about 73% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.