This image shows only the swells directed at Bridgetown Harbour that coincided with light winds or offshore conditions through a typical October and is based upon 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 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 frequently that size swell occurs.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was NNE, whereas the the prevailing wind blows from the E. 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 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal October but 20% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 20%, equivalent to (6 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Bridgetown Harbour is quite sheltered from open water swells, we estimate that clean surf can be found at Bridgetown Harbour about 0.2% of the time and that surf is spoilt by onshore wind -1% of the time. This is means that we expect -0 days with waves in a typical October, 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.