The graph describes the combination of swells directed at Ostiones over a normal February, based on 1584 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Ostiones. In the case of Ostiones, the best grid node is 15 km away (9 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 3% of the time. Green and yellow represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the most common swell direction, shown by the biggest spokes, was WSW, whereas the the dominant wind blows from the N. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ostiones and away from the coast. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Ostiones, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical February, swells large enough to cause good for surfing waves at Ostiones run for about 97% of the time.
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.