The figure shows the combination of swells directed at Trants Bay/Spleef Reef through an average November, based on 1680 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Trants Bay/Spleef Reef, and at Trants Bay/Spleef Reef the best grid node is 31 km away (19 miles).

The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These occurred only 17% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell occurs.

The diagram indicates that the most common swell direction, shown by the longest spokes, was NNE, whereas the the prevailing wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Trants Bay/Spleef Reef and out to sea. We lump these in 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 Trants Bay/Spleef Reef, 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 November, swells large enough to cause clean enough to surf waves at Trants Bay/Spleef Reef run for about 83% 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.