Ala Moana Swell Statistics, June: All Swell – Any Wind
The rose diagram illustrates the combination of swells directed at Ala Moana through an average June. It is based on 2306 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the most applicable grid node based on what we know about Ala Moana. In the case of Ala Moana, the best grid node is 39 km away (24 miles).
The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 0% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In each graph, 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 SSW, whereas the the most common wind blows from the S. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ala Moana and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Ala Moana, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause surfable waves at Ala Moana run for about 100% 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.