The rose diagram shows only the swells directed at Kerloch that coincided with light winds or offshore conditions through a typical northern hemisphere winter. It is based on 5048 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 show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the most common swell direction, shown by the biggest spokes, was W (which was the same as the dominant wind direction). 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 20% of the time, equivalent to 18 days. Expect open water swells to exceed >3m (>10ft) 2.0% of the time (2 days). Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Kerloch is exposed to open water swells, we calculate that clean surf can be found at Kerloch about 20% of the time and that surf is blown out by onshore wind 53% of the time. This is means that we expect 66 days with waves in a typical northern hemisphere winter, of which 18 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.