Wailua/Horners Swell Statistics, July: All Swell – Any Wind
The figure describes the combination of swells directed at Wailua/Horners through an average July, based on 2350 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the optimum grid node based on what we know about Wailua/Horners. In the case of Wailua/Horners, the best grid node is 35 km away (22 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 85% of the time. Green and yellow show increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the biggest spokes, was NNE, whereas the the dominant wind blows from the ENE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Wailua/Horners and out to sea. We combine these 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 clean enough to surf at Wailua/Horners, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause surfable waves at Wailua/Horners run for about 15% 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.