Ahu Ahu Road Swell Statistics, Autumn: 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 over a normal southern hemisphere autumn and is based upon 6580 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 highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the prevailing swell direction, shown by the longest spokes, was WSW (which was the same as the dominant 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 36% of the time, equivalent to 33 days. Open water swells exceeding >3m (>10ft) only occur 0.6% of the time in a typical southern hemisphere autumn, equivalent to just one day but 6% of the time we expect swell in the range 2-3m (6.5-10ft) 6%, equivalent to (5 days). Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Ahu Ahu Road is exposed to open water swells, we estimate that clean surf can be found at Ahu Ahu Road about 36% of the time and that surf is blown out by onshore wind 56% of the time. This is means that we expect 84 days with waves in a typical southern hemisphere autumn, of which 33 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.