This image shows only the swells directed at Lorient that coincided with light winds or offshore conditions through a typical November. It is based on 1680 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 red illustrates biggest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the most common swell direction, shown by the largest spokes, was NE, 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 62% of the time, equivalent to 19 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal November but 5% of the time we expect swell in the range 2-3m (6.5-10ft) 5%, equivalent to (2 days). Taking into account the proportion of these swells that coincided with predicted offshore winds we estimate that clean surf can be found at Lorient about 62% of the time and that surf is spoilt by onshore wind 36% of the time. This is means that we expect 29 days with waves in a typical November, of which 19 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.