Ala Moana Swell Statistics, October: Surf with Light or Offshore Winds
This image shows only the swells directed at Ala Moana that coincided with light winds or offshore conditions through a typical October. It is based on 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 illustrate increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the dominant swell direction, shown by the largest spokes, was SW, whereas the the dominant wind blows from the S. 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 0.3% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal October. Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Ala Moana is exposed to open water swells, we estimate that clean surf can be found at Ala Moana about 0.3% of the time and that surf is blown out by onshore wind 100% of the time. This is means that we expect 31 days with waves in a typical October, of which 0 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.