Assateague Swell Statistics, All Year: Surf with Light or Offshore Winds
This image shows only the swells directed at Assateague that coincided with light winds or offshore conditions through a typical year and is based upon 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 show increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each 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 largest spokes, was SE, whereas the the prevailing wind blows from the W. 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 30% of the time, equivalent to 110 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal year but 1.4% of the time we expect swell in the range 2-3m (6.5-10ft) 1.4%, equivalent to (5 days). Taking into account the proportion of these swells that coincided with forecast offshore winds, and given the fact that Assateague is exposed to open water swells, we estimate that clean surf can be found at Assateague about 30% of the time and that surf is blown out by onshore wind 40% of the time. This is means that we expect 256 days with waves in a typical year, of which 110 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.