Ann Street Peaks Swell Statistics, All Year: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Ann Street Peaks that coincided with light winds or offshore conditions over a normal year. It is based on 28044 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the prevailing swell direction, shown by the longest spokes, was ESE (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 16% of the time, equivalent to 58 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal year but 1.5% of the time we expect swell in the range 2-3m (6.5-10ft) 1.5%, equivalent to (5 days). Taking into account the proportion of these swells that coincided with expected offshore winds, and given the fact that Ann Street Peaks is exposed to open water swells, we calculate that clean surf can be found at Ann Street Peaks about 16% of the time and that surf is messed up by onshore wind 70% of the time. This is means that we expect 314 days with waves in a typical year, of which 58 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.