Napatree Jetty Swell Statistics, All Year: All Swell – Any Wind
The figure illustrates the combination of swells directed at Napatree Jetty over a normal year and is based upon 22223 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Napatree Jetty, and at Napatree Jetty the best grid node is 36 km away (22 miles).
The rose diagram describes 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 39% of the time. Green and yellow illustrate increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was SE, 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 Napatree Jetty and out to sea. We combine 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 good for surfing at Napatree Jetty, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical year, swells large enough to cause clean enough to surf waves at Napatree Jetty run for about 61% 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.