Aberavon Swell Statistics, Winter: Surf with Light or Offshore Winds
This image shows only the swells directed at Aberavon that coincided with light winds or offshore conditions through a typical northern hemisphere winter and is based upon 6931 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow represent increasing swell sizes and red represents largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the most common swell direction, shown by the largest spokes, was WSW (which was the same as the most common 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 15% of the time, equivalent to 14 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal northern hemisphere winter but 1.9% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 1.9%, equivalent to (2 days). Taking into account the proportion of these swells that coincided with expected offshore winds, and given the fact that Aberavon is exposed to open water swells, we calculate that clean surf can be found at Aberavon about 15% of the time and that surf is messed up by onshore wind 67% of the time. This is means that we expect 75 days with waves in a typical northern hemisphere winter, of which 14 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.