Ehukai/Gums Swell Statistics, Spring: All Swell – Any Wind
This chart describes the variation of swells directed at Ehukai/Gums over a normal northern hemisphere spring and is based upon 6580 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the most applicable grid node based on what we know about Ehukai/Gums. In the case of Ehukai/Gums, the best grid node is 39 km away (24 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 53% of the time. Green and yellow illustrate increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the most common swell direction, shown by the largest spokes, was NNW, whereas the the dominant wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ehukai/Gums and away from the coast. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Ehukai/Gums, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical northern hemisphere spring, swells large enough to cause surfable waves at Ehukai/Gums run for about 47% 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.