Arrieta Swell Statistics, June: Surf with Light or Offshore Winds
This image shows only the swells directed at Arrieta that coincided with light winds or offshore conditions over a normal June. It is based on 2306 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 illustrates the highest 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 longest spokes, was NNW (which was the same as the dominant wind direction). 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 0.9% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal June but 7% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 7%, equivalent to (2 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Arrieta is quite sheltered from open water swells, we estimate that clean surf can be found at Arrieta about 0.9% of the time and that surf is spoilt by onshore wind 17% of the time. This is means that we expect 5 days with waves in a typical June, of which 0 days should be clean enough to surf.
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.