Aropaonui Swell Statistics, All Year: Surf with Light or Offshore Winds
This image shows only the swells directed at Aropaonui that coincided with light winds or offshore conditions through a typical year. It is based on 28040 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow show increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the longest spokes, was ESE, whereas the the prevailing wind blows from the WNW. 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 38% of the time, equivalent to 139 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal year but 0.8% of the time we expect swell in the range 2-3m (6.5-10ft) 0.8%, equivalent to (3 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Aropaonui is exposed to open water swells, we calculate that clean surf can be found at Aropaonui about 38% of the time and that surf is spoilt by onshore wind 38% of the time. This is means that we expect 277 days with waves in a typical year, of which 139 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.