Aticama Swell Statistics, Agosto: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Aticama that coincided with light winds or offshore conditions through a typical August and is based upon 2480 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 show increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was SSW, whereas the the prevailing wind blows from the W. 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 54% of the time, equivalent to 17 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal August but 8% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 8%, equivalent to (2 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Aticama is exposed to open water swells, we estimate that clean surf can be found at Aticama about 54% of the time and that surf is blown out by onshore wind 35% of the time. This is means that we expect 28 days with waves in a typical August, of which 17 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.