This chart describes the variation of swells directed at Great and Little Carrot Bays through an average January. It is based on 2868 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the most applicable grid node based on what we know about Great and Little Carrot Bays. In the case of Great and Little Carrot Bays, the best grid node is 20 km away (12 miles).
The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but 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 47% 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 commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the biggest spokes, was NNE, whereas the the dominant wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Great and Little Carrot Bays and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Great and Little Carrot Bays, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical January, swells large enough to cause surfable waves at Great and Little Carrot Bays run for about 53% of the time.