Seabrook Beach Swell Statistics, All Year: All Swell – Any Wind
This image describes the variation of swells directed at Seabrook Beach over a normal year, based on 22227 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 Seabrook Beach. In this particular case the best grid node is 29 km away (18 miles).
The rose diagram describes the distribution of swell sizes and directions, 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 happened 42% of the time. Green and yellow show increasing swell sizes and red represents highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the most common swell direction, shown by the longest spokes, was ESE, whereas the the dominant 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 Seabrook Beach and out to sea. 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 good for surfing at Seabrook Beach, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical year, swells large enough to cause clean enough to surf waves at Seabrook Beach run for about 58% 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.