Agnes Waters Swell Statistics, December: Surf with Light or Offshore Winds
This image shows only the swells directed at Agnes Waters 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow represent increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the most common swell direction, shown by the longest spokes, was ENE (which was the same as the most common 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 5% of the time, equivalent to 2 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal December. Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Agnes Waters is exposed to open water swells, we calculate that clean surf can be found at Agnes Waters about 5% of the time and that surf is messed up by onshore wind 68% of the time. This is means that we expect 22 days with waves in a typical December, of which 2 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.