Andrew Molera State Park Swell Statistics, Autumn: Surf with Light or Offshore Winds
This image shows only the swells directed at Andrew Molera State Park that coincided with light winds or offshore conditions through a typical northern hemisphere autumn. It is based on 7252 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 represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either 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 largest spokes, was WNW, whereas the the dominant wind blows from the NNW. 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 47% of the time, equivalent to 43 days. Expect open water swells to exceed >3m (>10ft) 3% of the time (3 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Andrew Molera State Park is exposed to open water swells, we calculate that clean surf can be found at Andrew Molera State Park about 47% of the time and that surf is messed up by onshore wind 44% of the time. This is means that we expect 83 days with waves in a typical northern hemisphere autumn, of which 43 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.