Agucadoura Swell Statistics, December: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Agucadoura that coincided with light winds or offshore conditions through a typical December and is based upon 2457 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 largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the longest spokes, was WNW, whereas the the most common wind blows from the ESE. 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 44% of the time, equivalent to 13 days. Open water swells exceeding >3m (>10ft) only arise 3% of the time in a typical December, equivalent to just one day but 16% of the time we expect swell in the range 2-3m (6.5-10ft) 16%, equivalent to (5 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Agucadoura is exposed to open water swells, we calculate that clean surf can be found at Agucadoura about 44% of the time and that surf is blown out by onshore wind 54% of the time. This is means that we expect 29 days with waves in a typical December, of which 13 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.