Asilomar Swell Statistics, December: Surf with Light or Offshore Winds
This image shows only the swells directed at Asilomar that coincided with light winds or offshore conditions over a normal December and is based upon 2457 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 biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was WNW, whereas the the prevailing 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 50% of the time, equivalent to 15 days. Expect open water swells to exceed >3m (>10ft) 8% of the time (2 days). Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Asilomar is exposed to open water swells, we calculate that clean surf can be found at Asilomar about 50% of the time and that surf is messed up by onshore wind 49% of the time. This is means that we expect 30 days with waves in a typical December, of which 15 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.