This image illustrates the combination of swells directed at Henrys through a typical January, based on 1728 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 optimum grid node based on what we know about Henrys. In the case of Henrys, the best grid node is 27 km away (17 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without 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 occurred only 91% of the time. Green and yellow represent increasing swell sizes and red shows largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the longest spokes, was W, whereas the the most common wind blows from the NE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Henrys 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 plot. Because wind determines whether or not waves are good for surfing at Henrys, 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 January, swells large enough to cause clean enough to surf waves at Henrys run for about 9% 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.