Bobby's Swell Statistics, Summer: All Swell – Any Wind
This picture describes the range of swells directed at Bobby's through an average northern hemisphere summer and is based upon 7266 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the most applicable grid node based on what we know about Bobby's, and at Bobby's the best grid node is 20 km away (12 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, 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 were forecast only 9% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was WNW, whereas the the dominant wind blows from the NNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Bobby's and out to sea. We group 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 good for surfing at Bobby's, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical northern hemisphere summer, swells large enough to cause clean enough to surf waves at Bobby's run for about 91% 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.