Surf forecastStatisticsHistorical report

Prainha seasonal overview

Best Surf Season (October - March)

The North Atlantic winter machine is in full swing, delivering a relentless pulse of powerful, long-period swell to Prainha's west-facing shores. Average wave heights sit consistently between 2.5m and 2.8m with periods averaging 12-13s, meaning clean, lined-up waves are the norm. Offshore winds from the NO (NW) to OSO (WSW) quadrant occur 37-44% of the time, often aligning with passing cold fronts and post-frontal high-pressure ridges. This is the prime window for epic sessions – expect heavy, grinding barrels and long walls when a solid W or WNW swell meets light easterly morning wind.

Fair Surf Season (April - May & September)

As the atmosphere transitions, the power dials back a notch but quality remains high on the right days. April and May see average heights drop to 1.8-2.1m with periods around 10-11s, while September sees a sharp uptick in swell activity as early autumn storms begin to spin up. Wind consistency improves, with ideal offshore conditions occurring 24-31% of the time. These shoulder months often deliver the best combination of manageable size, lighter winds, and uncrowded lineups – perfect for carving up fun, rippable walls without the winter crowds.

Low Surf Season (June - August)

Summer sets in with a persistent northerly wind regime that keeps the ocean ragged and the swell small. Average wave heights hover around 1.5-1.6m, and periods drop to 8-9s, leaving the waves weak and choppy. The dominant N and NNW winds blow 30-35% of the time, creating onshore conditions that kill the wave quality. While the rare S-SW groundswell can sneak in, it’s typically small and short-lived. This is the time for groveling on a longboard or chasing wind protection; the magic of Prainha’s winter power is on hold until the autumn equinox signals the return of the North Atlantic.

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Conditions at Prainha in September

September: Autumn Stirrings

September is the transitional month where Prainha starts to wake up. Average swell height climbs to 1.7m and period lengthens to 10.5s – a noticeable improvement. Swell direction shifts back: NW (33.5%) and NNW (33.1%) still dominate, but WNW (15.5%) and W (4.1%) become more significant. Ideal wind conditions rise to 31%, a big jump from summer. N winds (31.6%) are still the most common, but NNW winds decrease to 20.0%. The east and southeast winds (E, ESE, SE) combine for 4.2% and are often light, providing glassy conditions. Early autumn storms begin to send groundswell pulses, and the combination of a building W-NW swell with early morning east wind can produce excellent waves. September is a great month to start watching the forecast again.

Average Spot conditions at Prainha in September

Swell history for September

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

Wind history for September

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

Swell quality

Analyze the groundswell consistency at Prainha 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 Prainha for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Prainha 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 Prainha.

Swell with good wind

Swell with good wind by size