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Jacobs Bay ratings
Quality on a good day: 4.0
Consistency of Surf: 3.0
Difficulty Level: 1.0
Crowds: 3.0

Overall: 3.2

See all 18 ratings

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Surf Report Feed

Jacobs Bay Swell Statistics, September: Surf with Light or Offshore Winds

This image shows only the swells directed at Jacobs Bay that coincided with light winds or offshore conditions through a typical September and is based upon 2880 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell was forecast.

The diagram suggests that the prevailing swell direction, shown by the longest spokes, was SW (which was the same as the prevailing wind direction). 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 20% of the time, equivalent to 6 days. Open water swells exceeding >3m (>10ft) only occur 4% of the time in a typical September, equivalent to just one day but 12% of the time we expect swell in the range 2-3m (6.5-10ft) 12%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Jacobs Bay is exposed to open water swells, we estimate that clean surf can be found at Jacobs Bay about 20% of the time and that surf is messed up by onshore wind 78% of the time. This is means that we expect 29 days with waves in a typical September, of which 6 days should be clean enough to surf.

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.