Algarrobo Swell Statistics, July: Surf with Light or Offshore Winds
This image shows only the swells directed at Algarrobo that coincided with light winds or offshore conditions through a typical July. It is based on 2480 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, 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 biggest spokes, was WSW, whereas the the most common wind blows from the S. 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 22% of the time, equivalent to 7 days. Open water swells exceeding >3m (>10ft) only happen 3% of the time in a typical July, equivalent to just one day but 11% of the time we expect swell in the range 2-3m (6.5-10ft) 11%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Algarrobo is exposed to open water swells, we estimate that clean surf can be found at Algarrobo about 22% of the time and that surf is messed up by onshore wind 77% of the time. This is means that we expect 31 days with waves in a typical July, of which 7 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.