This image describes the variation of swells directed at Mouse Rock over a normal November, based on 1680 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 optimum grid node based on what we know about Mouse Rock. In the case of Mouse Rock, the best grid node is 50 km away (31 miles).
The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks 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 4% of the time. Green and yellow represent 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 occurs.
The diagram indicates that the most common swell direction, shown by the longest spokes, was WNW, whereas the the dominant wind blows from the NNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Mouse Rock and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Mouse Rock, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause clean enough to surf waves at Mouse Rock run for about 96% 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.