Andrew Molera State Park Swell Statistics, December: 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 December. It is based on 2457 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 show increasing swell sizes and red represents 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 dominant swell direction, shown by the largest spokes, was WNW, whereas the the dominant wind blows from the NNE. 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 58% of the time, equivalent to 17 days. Expect open water swells to exceed >3m (>10ft) 7% of the time (2 days). Taking into account the proportion of these swells that coincided with expected offshore winds, and given the fact that Andrew Molera State Park is exposed to open water swells, we estimate that clean surf can be found at Andrew Molera State Park about 58% of the time and that surf is blown out by onshore wind 41% of the time. This is means that we expect 30 days with waves in a typical December, of which 17 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.