Abereiddy Swell Statistics, October: Surf with Light or Offshore Winds
This image shows only the swells directed at Abereiddy that coincided with light winds or offshore conditions over a normal October and is based upon 2480 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 represents the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the largest spokes, was SW, whereas the the prevailing wind blows from the SW. 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 14% of the time, equivalent to 4 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal October but 6% of the time we expect swell in the range 2-3m (6.5-10ft) 6%, equivalent to (2 days). Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Abereiddy is slightly protected from open water swells, we think that that clean surf can be found at Abereiddy about 14% of the time and that surf is spoilt by onshore wind 34% of the time. This is means that we expect 15 days with waves in a typical October, of which 4 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.