Aberavon Swell Statistics, January: All Swell – Any Wind
This chart describes the combination of swells directed at Aberavon through a typical January, based on 2372 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 optimum grid node based on what we know about Aberavon. In this particular case the best grid node is 16 km away (10 miles).
The rose diagram illustrates the distribution of swell sizes and swell direction, 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 18% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the biggest spokes, was WSW (which was the same as the dominant wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Aberavon and away from the coast. We group these 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 surfable at Aberavon, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average January, swells large enough to cause good for surfing waves at Aberavon run for about 82% 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.