Aberwystwyth Beach Swell Statistics, Summer: All Swell – Any Wind
The figure describes the combination of swells directed at Aberwystwyth Beach through a typical northern hemisphere summer and is based upon 7261 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the optimum grid node based on what we know about Aberwystwyth Beach. In the case of Aberwystwyth Beach, the best grid node is 29 km away (18 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast 48% of the time. Green and yellow represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the most common swell direction, shown by the biggest spokes, was WSW (which was the same as the dominant wind direction). Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Aberwystwyth Beach and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Aberwystwyth Beach, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average northern hemisphere summer, swells large enough to cause clean enough to surf waves at Aberwystwyth Beach run for about 12% 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.