Aisling's Beach Swell Statistics, September: Surf with Light or Offshore Winds
This image shows only the swells directed at Aisling's Beach that coincided with light winds or offshore conditions over a normal September. It is based on 2400 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the most common swell direction, shown by the longest spokes, was SE, whereas the the prevailing wind blows from the WNW. 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 39% of the time, equivalent to 12 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal September but 9% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 9%, equivalent to (3 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Aisling's Beach is exposed to open water swells, we think that that clean surf can be found at Aisling's Beach about 39% of the time and that surf is messed up by onshore wind 22% of the time. This is means that we expect 18 days with waves in a typical September, of which 12 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.