Arica Swell Statistics, Summer: Surf with Light or Offshore Winds
This image shows only the swells directed at Arica that coincided with light winds or offshore conditions through a typical southern hemisphere summer and is based upon 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 biggest swells greater than >3m (>10ft). In both graphs, 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 SW, whereas the the prevailing 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 11% of the time, equivalent to 10 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal southern hemisphere summer but 8% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 8%, equivalent to (7 days). Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Arica is exposed to open water swells, we think that that clean surf can be found at Arica about 11% of the time and that surf is spoilt by onshore wind 88% of the time. This is means that we expect 90 days with waves in a typical southern hemisphere summer, of which 10 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.