This image shows only the swells directed at Ventura Point that coincided with light winds or offshore conditions through a typical northern hemisphere autumn. It is based on 5144 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 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 biggest spokes, was W, whereas the the prevailing wind blows from the WNW. 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 8% of the time, equivalent to 7 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal northern hemisphere autumn but 2% of the time we expect swell in the range 2-3m (6.5-10ft) 2%, equivalent to (2 days). Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Ventura Point is slightly protected from open water swells, we think that that clean surf can be found at Ventura Point about 8% of the time and that surf is blown out by onshore wind 20% of the time. This is means that we expect 25 days with waves in a typical northern hemisphere autumn, of which 7 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.