This image shows only the swells directed at Aberaeron that coincided with light winds or offshore conditions over a normal northern hemisphere autumn. It is based on 4893 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow show increasing swell sizes and red shows highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the dominant swell direction, shown by the longest spokes, was SW (which was the same as the dominant wind direction). The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 3% of the time, equivalent to 3 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal northern hemisphere autumn but 2% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 2%, equivalent to (2 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Aberaeron is slightly protected from open water swells, we think that that clean surf can be found at Aberaeron about 3% of the time and that surf is messed up by onshore wind 28% of the time. This is means that we expect 28 days with waves in a typical northern hemisphere autumn, of which 3 days should be surfable.
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.