This image illustrates the variation of swells directed at Connecticut Street Jetty over a normal October. It is based on 1736 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the most applicable grid node based on what we know about Connecticut Street Jetty. In the case of Connecticut Street Jetty, the best grid node is 19 km away (12 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing 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 happened only 52% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the dominant swell direction, shown by the longest spokes, was SSE, whereas the the most common wind blows from the W. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Connecticut Street Jetty and out to sea. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Connecticut Street Jetty, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical October, swells large enough to cause surfable waves at Connecticut Street Jetty run for about 48% 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.