Apollo Bay Swell Statistics, Autumn: Surf with Light or Offshore Winds
This image shows only the swells directed at Apollo Bay 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 represent increasing swell sizes and red represents the highest swells, greater than >3m (>10ft). In both graphs, 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 SW, 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 49% of the time, equivalent to 45 days. Expect open water swells to exceed >3m (>10ft) 18% of the time (16 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Apollo Bay is slightly protected from open water swells, we calculate that clean surf can be found at Apollo Bay about 49% of the time and that surf is messed up by onshore wind 48% of the time. This is means that we expect 88 days with waves in a typical southern hemisphere autumn, of which 45 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.