Statistiques de Houle pour Anglet - La Madrague, Avril: Vagues avec Vents Légers ou Favorables.
This image shows only the swells directed at Anglet - La Madrague that coincided with light winds or offshore conditions over a normal April. It is based on 2160 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 represents 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 longest spokes, was WNW (which was the same as the prevailing 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 32% of the time, equivalent to 10 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal April but 12% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 12%, equivalent to (4 days). Taking into account the ratio of these swells that coincided with predicted offshore winds, and given the fact that Anglet - La Madrague is exposed to open water swells, we think that that clean surf can be found at Anglet - La Madrague about 32% of the time and that surf is messed up by onshore wind 56% of the time. This is means that we expect 26 days with waves in a typical April, of which 10 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.