Tolaga Bay Swell Statistics, Spring: All Swell – Any Wind
This image shows the range of swells directed at Tolaga Bay through an average southern hemisphere spring. It is based on 6516 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 Tolaga Bay. In this particular case the best grid node is 21 km away (13 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without 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 52% of the time. Green and yellow show increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the dominant swell direction, shown by the longest spokes, was E, whereas the the prevailing wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Tolaga 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 Tolaga 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 southern hemisphere spring, swells large enough to cause clean enough to surf waves at Tolaga Bay run for about 48% 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.