Kanaha Swell Statistics, March: All Swell – Any Wind
The rose diagram shows the combination of swells directed at Kanaha over a normal March and is based upon 2090 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about Kanaha. In the case of Kanaha, the best grid node is 13 km away (8 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 43% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the biggest spokes, was NNE, whereas the the prevailing 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 group 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 surfable at Kanaha, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical March, swells large enough to cause good for surfing waves at Kanaha run for about 57% 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.