The rose diagram shows only the swells directed at Lorient that coincided with light winds or offshore conditions through a typical January. It is based on 1728 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 red shows the biggest swells, greater than >3m (>10ft). In each graph, 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 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 59% of the time, equivalent to 18 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal January but 10% of the time we expect swell in the range 2-3m (6.5-10ft) 10%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with predicted offshore winds we think that that clean surf can be found at Lorient about 59% of the time and that surf is blown out by onshore wind 37% of the time. This is means that we expect 30 days with waves in a typical January, of which 18 days should be clean enough to surf.
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.