This image shows only the swells directed at Westfalia that coincided with light winds or offshore conditions through a typical August. It is based on 1736 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow represent 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 often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the longest spokes, was ENE, whereas the the prevailing wind blows from the NW. 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 79% of the time, equivalent to 24 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal August but 22% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 22%, equivalent to (7 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Westfalia is exposed to open water swells, we estimate that clean surf can be found at Westfalia about 79% of the time and that surf is spoilt by onshore wind 15% of the time. This is means that we expect 29 days with waves in a typical August, of which 24 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.