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Chapel Porth ratings
Quality on a good day: 3.0
Consistency of Surf: 5.0
Difficulty Level: 3.0
Crowds: 2.0

Overall: 3.3

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Surf Report Feed

Chapel Porth Swell Statistics, Autumn: Surf with Light or Offshore Winds

The rose diagram shows only the swells directed at Chapel Porth that coincided with light winds or offshore conditions through a typical northern hemisphere autumn. It is based on 7252 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow illustrate increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell occurs.

The diagram implies that the prevailing swell direction, shown by the longest spokes, was W, whereas the the dominant wind blows from the WSW. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 15% of the time, equivalent to 14 days. Open water swells exceeding >3m (>10ft) only happen 0.6% of the time in a typical northern hemisphere autumn, equivalent to just one day but 6% of the time we expect swell in the range 2-3m (6.5-10ft) 6%, equivalent to (5 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Chapel Porth is slightly protected from open water swells, we calculate that clean surf can be found at Chapel Porth about 15% of the time and that surf is messed up by onshore wind 51% of the time. This is means that we expect 60 days with waves in a typical northern hemisphere autumn, of which 14 days should be surfable.

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.