Ano Nuevo Swell Statistics, January: Surf with Light or Offshore Winds
This image shows only the swells directed at Ano Nuevo that coincided with light winds or offshore conditions over a normal January. It is based on 2372 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 the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the longest spokes, was W, 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 10% of the time, equivalent to 3 days. Open water swells exceeding >3m (>10ft) only happen 3% of the time in a typical January, equivalent to just one day but 7% of the time we expect swell in the range 2-3m (6.5-10ft) 7%, equivalent to (2 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Ano Nuevo is quite sheltered from open water swells, we calculate that clean surf can be found at Ano Nuevo about 10% of the time and that surf is spoilt by onshore wind 16% of the time. This is means that we expect 8 days with waves in a typical January, of which 3 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.