Herolds Bay Swell Statistics, December: All Swell – Any Wind
This image illustrates the range of swells directed at Herolds Bay over a normal December. It is based on 1961 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about Herolds Bay. In the case of Herolds Bay, the best grid node is 52 km away (32 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, 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 happened only 76% of the time. Green and yellow show 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 largest spokes, was ESE, whereas the the most common wind blows from the SSE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Herolds Bay and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Herolds Bay, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical December, swells large enough to cause surfable waves at Herolds Bay run for about 24% 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.