Aisling's Beach Swell Statistics, May: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Aisling's Beach that coincided with light winds or offshore conditions over a normal May. It is based on 2200 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 show increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was SE, whereas the the prevailing wind blows from the W. 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 57% of the time, equivalent to 18 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal May but 11% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 11%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Aisling's Beach is exposed to open water swells, we calculate that clean surf can be found at Aisling's Beach about 57% of the time and that surf is blown out by onshore wind 17% of the time. This is means that we expect 23 days with waves in a typical May, of which 18 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.