Aberavon Swell Statistics, Spring: All Swell – Any Wind
This picture illustrates the range of swells directed at Aberavon through an average northern hemisphere spring. It is based on 6579 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 best grid node based on what we know about Aberavon. In the case of Aberavon, the best grid node is 16 km away (10 miles).
The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred 35% of the time. Green and yellow represent increasing swell sizes and red illustrates largest 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, whereas the the most common wind blows from the W. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Aberavon 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 Aberavon, 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 northern hemisphere spring, swells large enough to cause clean enough to surf waves at Aberavon run for about 65% 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.