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Piha-The Ditch ratings
Quality on a good day: 3.0
Consistency of Surf: 3.0
Difficulty Level: 3.0
Crowds: 3.0

Overall: 3.2

See all 18 ratings

Based on 3 votes. Vote


Surf Report Feed

Piha-The Ditch Swell Statistics, March: All Swell – Any Wind

The graph illustrates the range of swells directed at Piha-The Ditch through a typical March. It is based on 2964 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Piha-The Ditch, and at Piha-The Ditch the best grid node is 6 km away (4 miles).

The rose diagram shows the distribution of swell directions and swell sizes, 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 2% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.

The diagram suggests that the dominant swell direction, shown by the longest spokes, was WSW, whereas the the most common wind blows from the SSE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Piha-The Ditch and out to sea. 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 Piha-The Ditch, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average March, swells large enough to cause good for surfing waves at Piha-The Ditch run for about 98% 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.