Arpoador Swell Statistics, January: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Arpoador that coincided with light winds or offshore conditions through a typical January. It is based on 2372 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 illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was SE, whereas the the dominant wind blows from the NE. 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 16% of the time, equivalent to 5 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal January but 14% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 14%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Arpoador is slightly protected from open water swells, we think that that clean surf can be found at Arpoador about 16% of the time and that surf is messed up by onshore wind 9% of the time. This is means that we expect 8 days with waves in a typical January, 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.