Ajo Swell Statistics, December: Surf with Light or Offshore Winds
This image shows only the swells directed at Ajo 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 represent increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was NW, whereas the the prevailing wind blows from the SSW. 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 14 days. Open water swells exceeding >3m (>10ft) only arise 4% of the time in a typical December, equivalent to just one day but 17% of the time we expect swell in the range 2-3m (6.5-10ft) 17%, equivalent to (5 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Ajo is exposed to open water swells, we estimate that clean surf can be found at Ajo about 47% of the time and that surf is spoilt by onshore wind 47% of the time. This is means that we expect 28 days with waves in a typical December, of which 14 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.