Arica Swell Statistics, Winter: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Arica that coincided with light winds or offshore conditions through a typical southern hemisphere winter. It is based on 7266 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 show 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 was forecast.
The diagram implies that the dominant swell direction, shown by the longest 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 0.3% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal southern hemisphere winter. Taking into account the proportion of these swells that coincided with expected offshore winds, and given the fact that Arica is exposed to open water swells, we calculate that clean surf can be found at Arica about 0.3% of the time and that surf is spoilt by onshore wind 100% of the time. This is means that we expect 91 days with waves in a typical southern hemisphere winter, of which 0 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.