Augusta Rivermouth Swell Statistics, Autumn: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Augusta Rivermouth that coincided with light winds or offshore conditions over a normal southern hemisphere autumn. It is based on 6580 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 represents largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the most common swell direction, shown by the biggest spokes, was SSW, whereas the the most common wind blows from the SSE. 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 9% of the time, equivalent to 8 days. Expect open water swells to exceed >3m (>10ft) 3% of the time (3 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Augusta Rivermouth is slightly protected from open water swells, we calculate that clean surf can be found at Augusta Rivermouth about 9% of the time and that surf is spoilt by onshore wind 31% of the time. This is means that we expect 36 days with waves in a typical southern hemisphere autumn, of which 8 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.