Roberts Left Surf Stats

The graph illustrates the range of swells directed at Roberts Left through an average June. It is based on 3266 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Roberts Left. In this particular case the best grid node is 38 km away (24 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but 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 46% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the prevailing swell direction, shown by the longest spokes, was W, whereas the the most common wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Roberts Left and offshore. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Roberts Left, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause good for surfing waves at Roberts Left run for about 54% of the time.

read more