Hanalei Bay Swell Statistics, January: All Swell – Any Wind
This chart shows the combination of swells directed at Hanalei Bay through an average January, based on 2372 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable 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 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 were forecast only 14% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the dominant swell direction, shown by the longest spokes, was NNW, whereas the the prevailing 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 Hanalei Bay and out to sea. We group these with the no surf category of the bar chart. To avoid confusion 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 select a similar diagram 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 86% 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.