Arroyo Laguna Swell Statistics, Winter: Surf with Light or Offshore Winds
This image shows only the swells directed at Arroyo Laguna that coincided with light winds or offshore conditions through a typical northern hemisphere winter. It is based on 6931 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 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 commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was W, whereas the the prevailing 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 7% of the time, equivalent to 6 days. Open water swells exceeding >3m (>10ft) only happen 0.8% of the time in a typical northern hemisphere winter, equivalent to just one day but 3% of the time we expect swell in the range 2-3m (6.5-10ft) 3%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Arroyo Laguna is exposed to open water swells, we calculate that clean surf can be found at Arroyo Laguna about 7% of the time and that surf is spoilt by onshore wind 11% of the time. This is means that we expect 16 days with waves in a typical northern hemisphere winter, of which 6 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.