Ardmore Swell Statistics, All Year: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Ardmore that coincided with light winds or offshore conditions through a typical 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either 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 longest spokes, was SW, whereas the the dominant 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 0.2% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal year but 1.1% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 1.1%, equivalent to (4 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Ardmore is quite sheltered from open water swells, we estimate that clean surf can be found at Ardmore about 0.2% of the time and that surf is blown out by onshore wind 10% of the time. This is means that we expect 36 days with waves in a typical year, of which 1 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.