Surf forecastStatisticsHistorical report

Parlementia seasonal overview

Best Surf Season (October - March)

The North Atlantic flexes its muscles from October through March, delivering consistent, powerful groundswells that march straight into Parlementia's NW-facing bay. Average surf heights sit in the 1.3-1.8m range with periods of 11-13s, meaning you get pumping, heavy waves during the peak. Offshore winds (S/SSW/SW/WSW) blow 36-51% of the time, often triggered by highs building over the Bay of Biscay. The NAO index tends to be negative or neutral, steering the jet stream south and fuelling extratropical storms that send long-period WNW and NW swell right in. When it all aligns, Parlementia fires.

Fair Surf Season (April & September)

April and September are transitional months where the swell machine slows but still offers fun, rippable waves. Average heights dip to 1.1-1.2m with periods around 10.6-11.0s – still punchy, but less consistent. Offshore wind frequency drops to 29%, making it a game of reading the charts. The Azores High starts to nudge north in April and retreats in September, mixing in longer gaps between groundswells and more variable conditions. You won't score epic sessions every day, but when the combo works, the lineup is uncrowded and the waves are solid.

Low Surf Season (May - August)

Summer in the Bay of Biscay is a quiet affair. From May to August, average swell height hovers around 0.9-1.0m and periods drop to 9.0-10.1s – mostly small, fun-sized grovelers. The dominant NW windswell is often accompanied by onshore winds (W/WNW/NW/NNW) that blow 40-50% of the time, leaving only 15-23% offshore conditions. The Azores High parks itself over the region, producing light but often unfavourable breezes. While micro-sessions on a longboard are possible, don't expect firing waves. The odd late-summer hurricane remnant or distant low can produce a brief spike, but reliability is low.

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Conditions at Parlementia in September

September: The Turn of the Tide

September marks the beginning of the transition. Average swell height rises to 1.1m, period 10.6s – powerful starts to return. Swell direction is still NW (53.8%) and WNW (33.3%), but the height distribution shows more in the 1-2m range. Offshore wind frequency jumps to 29%, and the wind rose shifts: onshore W/WNW/NW winds decline slightly, while S and SSW winds (4.6% + 3.2%) begin to reappear. The first strong autumn lows can deliver solid groundswell with clean offshore winds when the timing is right. This is a month of increasing potential – not yet peak, but the odds of good waves improve every week.

Average Spot conditions at Parlementia 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 Parlementia 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 Parlementia for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Parlementia 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 Parlementia.

Swell with good wind

Swell with good wind by size