Surf forecastStatisticsHistorical report

Green Island seasonal overview

Best Surf Season (June – August)

As winter tightens its grip on the Southern Hemisphere, the Tasman Sea roars to life. The combination of strong frontal systems sweeping up from the Southern Ocean and a steady ridge of high pressure to the south funnels consistent, long-period S to SSE swells directly into the island's southeast-facing setup. Offshore flow from the prevailing NW to NNW winds becomes the norm, with ideal wind percentages peaking near 53% in July. This is Green Island at its finest – pumping, glassy, and firing.

Fair Surf Season (April – May & September – October)

The transitional shoulder months bring a mixed bag. Swell direction already favors the SE quadrant, and average heights hover around a solid 1.6-1.7m with periods stretching into the 8-9s range. However, the wind regime is more fickle – while offshore breezes dominate a decent chunk of the time, lingering onshore S to ESE pulses can chop up what would otherwise be pristine lines. Expect fun, rippable waves with occasional windows of perfection when a high-pressure system parks itself overhead.

Low Surf Season (November – March)

The summer months see a downturn in both swell quality and wind consistency. The storm tracks retreat poleward, leaving behind a diet of short-period, weaker E to NE swell that rarely aligns with the spot's optimal SE exposure. On top of that, the trade wind influence strengthens, with persistent ESE to S onshore winds ruining the groomed face. While the odd pulse from a tropical depression or a late-season cold front can salvage a session, the general rule of thumb is smaller, choppier and less reliable surf.

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Conditions at Green Island in May

May: Winter Preview – Consistent and Clean

May marks a turning point. The average swell height holds at 1.7m, but the period jumps to 9.3s, and the wind quality reaches 51% offshore – the best so far. Swell direction is now heavily favoring the S to SSE quadrant, with SSE contributing 18.5% and S a solid 14.8%. These are long-period groundswells that have marched thousands of miles from the Southern Ocean. The wind roses show a strong preference for W, WNW and NW winds, which blow straight offshore. The result is clean, groomed lines with minimal chop. When a deep low anchors off Tasmania, this spot can fire with waist-to-head-high sets wrapping perfectly into the bay. This is prime Green Island.

Average Spot conditions at Green Island in May

Swell history for May

0 - 0.5
0.5 - 1
1 - 1.5
1.5 - 2.0
2.0 - 2.5
> 2.5 m

Wind history for May

0 - 10
10 - 20
20 - 30
30 - 40
40 - 50
> 50 km/h

Swell quality

Analyze the groundswell consistency at Green Island during May. Based on historical data, there is a % probability of groundswell occurring this month. The chart below provides a detailed breakdown of the average wave height distribution, offering deep insights into the swell quality and surf potential you can expect at Green Island for your next trip in May.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Green Island for May. Our analysis shows that favorable offshore or side-shore winds coincide with surfable swell approximately % of the time. The accompanying graph illustrates the average size distribution of waves during these optimal wind windows at Green Island.

Swell with good wind

Swell with good wind by size