The rose diagram shows only the swells directed at Manresa State Beach that coincided with light winds or offshore conditions through a typical June. It is based on 1594 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 illustrates the largest 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 longest spokes, was WNW (which was the same as the most common 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 16% of the time, equivalent to 5 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal June but 9% of the time we expect swell in the range 2-3m (6.5-10ft) 9%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Manresa State Beach is exposed to open water swells, we estimate that clean surf can be found at Manresa State Beach about 16% of the time and that surf is messed up by onshore wind 62% of the time. This is means that we expect 23 days with waves in a typical June, of which 5 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.