Audierne Swell Statistics, Spring: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Audierne that coincided with light winds or offshore conditions through a typical northern hemisphere spring. It is based on 6580 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 illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was W, whereas the the prevailing wind blows from the NNW. 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 18% of the time, equivalent to 16 days. Open water swells exceeding >3m (>10ft) only happen 1.5% of the time in a typical northern hemisphere spring, equivalent to just one day but 6% of the time we expect swell in the range 2-3m (6.5-10ft) 6%, equivalent to (5 days). Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Audierne is slightly protected from open water swells, we calculate that clean surf can be found at Audierne about 18% of the time and that surf is blown out by onshore wind 35% of the time. This is means that we expect 48 days with waves in a typical northern hemisphere spring, of which 16 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.