Anawhata Road (Oaonui) Swell Statistics, Winter: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Anawhata Road (Oaonui) that coincided with light winds or offshore conditions through a typical southern hemisphere winter. It is based on 7266 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 represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the largest spokes, was WSW, whereas the the dominant wind blows from the W. 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 20% of the time, equivalent to 18 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal southern hemisphere winter but 7% of the time we expect swell in the range 2-3m (6.5-10ft) 7%, equivalent to (6 days). Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Anawhata Road (Oaonui) is exposed to open water swells, we calculate that clean surf can be found at Anawhata Road (Oaonui) about 20% of the time and that surf is messed up by onshore wind 59% of the time. This is means that we expect 72 days with waves in a typical southern hemisphere winter, of which 18 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.