Santa Maria - Anjos Swell Statistics, December: Surf with Light or Offshore Winds
This image shows only the swells directed at Santa Maria - Anjos that coincided with light winds or offshore conditions through a typical December. It is based on 2457 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 represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the dominant swell direction, shown by the biggest spokes, was NW, whereas the the prevailing wind blows from the SW. 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 21% of the time, equivalent to 6 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal December but 9% of the time we expect swell in the range 2-3m (6.5-10ft) 9%, equivalent to (3 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Santa Maria - Anjos is exposed to open water swells, we calculate that clean surf can be found at Santa Maria - Anjos about 21% of the time and that surf is messed up by onshore wind 51% of the time. This is means that we expect 22 days with waves in a typical December, of which 6 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.