This image shows only the swells directed at Shipwreck that coincided with light winds or offshore conditions through a typical July. 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 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 highest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the largest spokes, was SSW, whereas the the dominant wind blows from the SW. 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 1.6% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal July. Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Shipwreck is exposed to open water swells, we estimate that clean surf can be found at Shipwreck about 1.6% of the time and that surf is spoilt by onshore wind 98% of the time. This is means that we expect 31 days with waves in a typical July, of which 0 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.