Mahanga Beach Surf Stats

This picture shows the range of swells directed at Mahanga Beach through an average August, based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Mahanga Beach. In this particular case the best grid node is 10 km away (6 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 55% of the time. Green and yellow show increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates 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 out to sea, sometimes a strong offshore wind blows largest waves away from Mahanga Beach and offshore. We combine 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 surfable at Mahanga Beach, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause good for surfing waves at Mahanga Beach run for about 31% of the time.

read more