Riet River Swell Statistics, Summer: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Riet River that coincided with light winds or offshore conditions through a typical southern hemisphere summer. It is based on 6365 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 illustrate increasing swell sizes and red shows 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 longest spokes, was SSW, whereas the the dominant wind blows from the SE. 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 28% of the time, equivalent to 25 days. Expect open water swells to exceed >3m (>10ft) 4% of the time (4 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Riet River is exposed to open water swells, we calculate that clean surf can be found at Riet River about 28% of the time and that surf is messed up by onshore wind 47% of the time. This is means that we expect 68 days with waves in a typical southern hemisphere summer, of which 25 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.