The rose diagram shows only the swells directed at Rest Bay that coincided with light winds or offshore conditions through a typical August and is based upon 1735 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 illustrates highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was WSW (which was the same as the dominant wind direction). 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 0.2% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal August. Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Rest Bay is slightly protected from open water swells, we estimate that clean surf can be found at Rest Bay about 0.2% of the time and that surf is messed up by onshore wind 14% of the time. This is means that we expect 4 days with waves in a typical August, of which 0 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.