The graph illustrates the combination of swells directed at Big Wave Bay through an average June. It is based on 1594 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 most applicable grid node based on what we know about Big Wave Bay, and at Big Wave Bay the best grid node is 38 km away (24 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 96% of the time. Green and yellow represent increasing swell sizes and red shows largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was E, 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 Big Wave Bay and away from the coast. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Big Wave Bay, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause clean enough to surf waves at Big Wave Bay run for about 0% 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.