Santa Maria - Anjos Swell Statistics, September: 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 September and is based upon 2400 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 red illustrates 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 biggest spokes, was NW, whereas the the most common wind blows from the NNE. 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 17% of the time, equivalent to 5 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal September but 8% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 8%, equivalent to (2 days). Taking into account the fraction of these swells that coincided with predicted 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 17% of the time and that surf is spoilt by onshore wind 42% of the time. This is means that we expect 18 days with waves in a typical September, of which 5 days should be surfable.
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.