The rose diagram shows the variation of swells directed at Devil s Punch Beverly Beach through a typical February, based on 1584 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Devil s Punch Beverly Beach. In the case of Devil s Punch Beverly Beach, the best grid node is 44 km away (27 miles).
The rose diagram describes 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 1.7% of the time. Green and yellow show increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the most common swell direction, shown by the biggest spokes, was W, whereas the the prevailing wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Devil s Punch Beverly Beach and out to sea. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Devil s Punch Beverly Beach, 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 February, swells large enough to cause clean enough to surf waves at Devil s Punch Beverly Beach run for about 98% 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.