Ahu Ahu Road Swell Statistics, August: Surf with Light or Offshore Winds
This image shows only the swells directed at Ahu Ahu Road that coincided with light winds or offshore conditions through a typical August. 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 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 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 happens.
The diagram implies that the prevailing swell direction, shown by the longest spokes, was WSW (which was the same as the prevailing wind direction). 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 30% of the time, equivalent to 9 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal August but 8% of the time we expect swell in the range 2-3m (6.5-10ft) 8%, equivalent to (2 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Ahu Ahu Road is exposed to open water swells, we calculate that clean surf can be found at Ahu Ahu Road about 30% of the time and that surf is spoilt by onshore wind 61% of the time. This is means that we expect 28 days with waves in a typical August, of which 9 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.