Mystery Point Swell Statistics, All Year: All Swell – Any Wind
The rose diagram describes the combination of swells directed at Mystery Point through a typical year. It is based on 26700 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Mystery Point. In this particular case the best grid node is 26 km away (16 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 0.4% of the time. Green and yellow illustrate increasing swell sizes and red shows highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was NW, whereas the the dominant wind blows from the N. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Mystery Point and out to sea. We lump these in 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 Mystery Point, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average year, swells large enough to cause surfable waves at Mystery Point run for about 80% 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.