Mouse Rock Swell Statistics, December: All Swell – Any Wind
This chart describes the range of swells directed at Mouse Rock through a typical December, based on 2209 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 best grid node based on what we know about Mouse Rock, and at Mouse Rock the best grid node is 50 km away (31 miles).
The rose diagram illustrates 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 were forecast only 0.7% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, 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 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 combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Mouse Rock, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average December, swells large enough to cause good for surfing waves at Mouse Rock run for about 99% 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.