The graph illustrates the combination of swells directed at Damneck Naval Base through an average northern hemisphere summer. It is based on 5066 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Damneck Naval Base. In the case of Damneck Naval Base, the best grid node is 47 km away (29 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 27% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the most common swell direction, shown by the longest spokes, was ESE, whereas the the most common wind blows from the SSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Damneck Naval Base and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Damneck Naval Base, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical northern hemisphere summer, swells large enough to cause good for surfing waves at Damneck Naval Base 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.