Aberffraw Swell Statistics, June: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Aberffraw that coincided with light winds or offshore conditions over a normal June and is based upon 2305 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 illustrate increasing swell sizes and largest 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 dominant swell direction, shown by the biggest spokes, was WSW, whereas the the most common wind blows from the WSW. 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 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal June. Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Aberffraw is exposed to open water swells, we think that that clean surf can be found at Aberffraw about 3% of the time and that surf is messed up by onshore wind 29% of the time. This is means that we expect 10 days with waves in a typical June, of which 1 days should be clean enough to surf.
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.