Aberdeen Swell Statistics, Winter: Surf with Light or Offshore Winds
This image shows only the swells directed at Aberdeen that coincided with light winds or offshore conditions over a normal northern hemisphere winter and is based upon 6929 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 represents biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the most common swell direction, shown by the largest spokes, was SE, whereas the the prevailing wind blows from the WSW. 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 15 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal northern hemisphere winter but 4% of the time we expect swell in the range 2-3m (6.5-10ft) 4%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Aberdeen is exposed to open water swells, we calculate that clean surf can be found at Aberdeen about 17% of the time and that surf is messed up by onshore wind 31% of the time. This is means that we expect 44 days with waves in a typical northern hemisphere winter, of which 15 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.