All Day Bay Swell Statistics, Winter: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at All Day Bay that coincided with light winds or offshore conditions over a normal 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow show increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the dominant swell direction, shown by the biggest spokes, was SSE, whereas the the dominant 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 42% of the time, equivalent to 38 days. Expect open water swells to exceed >3m (>10ft) 2% of the time (2 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that All Day Bay is exposed to open water swells, we calculate that clean surf can be found at All Day Bay about 42% of the time and that surf is spoilt by onshore wind 30% of the time. This is means that we expect 66 days with waves in a typical southern hemisphere winter, of which 38 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.