Conset Point Swell Statistics, Summer: All Swell – Any Wind
The figure describes the variation of swells directed at Conset Point through an average northern hemisphere summer and is based upon 6864 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable grid node based on what we know about Conset Point. In this particular case the best grid node is 35 km away (22 miles).
The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks 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 35% of the time. Green and yellow show increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the dominant swell direction, shown by the biggest spokes, was E (which was the same as the dominant wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Conset Point and away from the coast. 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 clean enough to surf at Conset Point, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical northern hemisphere summer, swells large enough to cause surfable waves at Conset Point run for about 65% 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.