Hanalei Bay Swell Statistics, January: All Swell – Any Wind
This image illustrates the variation of swells directed at Hanalei Bay through an average January. It is based on 1925 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Hanalei Bay. In the case of Hanalei Bay, the best grid node is 31 km away (19 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing 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 16% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the dominant swell direction, shown by the largest spokes, was NNW, whereas the the most common wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Hanalei Bay and offshore. 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 good for surfing at Hanalei Bay, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical January, swells large enough to cause clean enough to surf waves at Hanalei Bay run for about 84% 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.