Gunnamatta seasonal overview
Best Surf Season (March - May)
Autumn steals the show at Gunnamatta. As the Southern Ocean begins to settle after the volatile winter, the frequency of high-pressure systems tracking across the Great Australian Bight increases. These systems are the catalyst for our best conditions: they generate long-period SW groundswells that slam into the SW-facing coastline with raw power, while simultaneously providing a stable easterly flow off the land. During these months, the average swell height sits around 1.4-1.5m with periods often pushing into the 12-second range, translating to powerful, rippable walls. More importantly, the ideal wind frequency peaks at 19-22%, meaning you can count on clean, offshore breezes from the NNE through E quadrant to groom the faces into perfection. This is the sweet spot – consistent swell, favourable winds, and comfortable air temperatures.
Fair Surf Season (September - November)
Spring marks a transitional period. The Roaring Forties are still active, firing up potent storm tracks that send powerful SW and WSW groundswells our way. Average heights climb to 1.5-1.7m with periods holding around 12-13s, offering plenty of punch. However, the wind game gets trickier. The clash between lingering winter systems and building spring highs brings more frequent onshore flows from the SW and WSW. Ideal wind days drop to 16-17%, so you'll need to pick your windows carefully. When the synoptic setup aligns – a cold front passing to the south followed by a strong high building in the Bight – you get the classic combo: clean offshore E winds and heavy, long-period lines wrapping into the beach.
Low Surf Season (December - February)
Summer at Gunnamatta is a trade-off. The swell engine slows down as the storm track retreats south, resulting in average heights dipping to 1.4m and periods settling around 11-11.5s. You'll still see plenty of SW swell, but it's often less consistent and lacks the top-end power of autumn and winter. The main issue is the wind. The persistent synoptic pattern of a trough sitting over the coast, combined with sea breezes, limits clean windows to around 14-16% of the time. Mornings offer the best chance for offshore flow from the NE before the SW seabreezes kick up by midday. While you can score fun, grovelly sessions on the smaller days, the real quality is hard to come by.
Loading chart...
Conditions at Gunnamatta in September
September: Spring Transition
September sees the beginning of the transition away from deep winter. The swell average remains high at 1.7m with a 12.9s period, but the wind ideal improves slightly to 16%. The swell direction is still dominated by SW (45%) and WSW (21%), with a notable increase in the 1.5-2.5m range. The storm tracks are still active, but the highs are starting to move further north, which can bring more easterly wind flows. The wind statistics show a reduction in northerly components and an increase in westerly and southwesterly flows, but those are onshore. The best windows are often associated with the passage of a strong cold front: the westerly winds will roar, but followed by a dramatic swing to the east-northeast as a high builds in. That post-frontal day can deliver perfect grooming on a heavy, long-period swell.
Average Spot conditions at Gunnamatta in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Gunnamatta during September. 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 Gunnamatta for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Gunnamatta for September. 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 Gunnamatta.
