Surf forecastStatisticsHistorical report

Sao Lourenco seasonal overview

Best Surf Season (October - March)

The North Atlantic roars to life during these months, delivering a consistent barrage of powerful, long-period swell generated by intense extratropical storms. Average wave heights range from 2.0m to 2.6m, with periods frequently exceeding 11 seconds, often reaching 12-13s — that's pumping, heavy surf. The dominant swell directions are from the WNW, NW, and NNW, which funnel directly into the spot's West-North-West exposure, producing clean, lined-up waves. Frontal passages often shift winds to favorable offshore directions (east to southeast), yielding ideal conditions about 20-25% of the time. Expect solid head-high to double-overhead sets, with occasional XL swells pushing past 2.5m. This is prime time for committed surfers chasing quality.

Fair Surf Season (April & September)

Spring and early autumn offer transitional windows with some quality waves. April sees the last pulses of winter energy, averaging 2.0m at 11.1s, with a focus on WNW-NW swell. The wind becomes more variable — ideal conditions drop to 13% — but clean, fun-sized days still occur. September marks the beginning of the autumn ramp-up, with average swell height at 1.6m and periods climbing back to 10.5s. Stronger storm activity in the North Atlantic starts to build, while wind patterns shift, offering occasional offshore windows (12% ideal). Expect fun, rippable waves, but consistency is lower than winter.

Low Surf Season (May - August)

Summer ushers in a persistent lull. Swell heights drop to 1.4-1.7m with periods shrinking to 8.5-9.9s, resulting in choppy, average conditions. The dominant swell shifts to NNW to NW, often generated by weaker distant storms or local windswell. The wind regime becomes dominated by strong northern trades (N, NNW) blowing 20-40 kph, which create onshore, bumpy surf and ruin quality. Ideal offshore wind is a rare commodity, occurring only 3-9% of the time. Waves are mostly small, groveling and messy, best left for longboards or smaller crafts. On the rare occasion when high pressure settles over the Bay of Biscay, light easterly winds can clean things up, but those days are few and far between.

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Conditions at Sao Lourenco in September

September: Autumn Awakening

September signals the start of the upward trend. Average swell height climbs to 1.6m, period to 10.5s — powerful, long period for the conditions. Swell direction becomes more varied: NW (36.0%) and NNW (34.4%) still dominate, but there is a growing contribution from WNW (15.4%) and W (4.4%). Wave heights in the 1-2m range become more common, offering solid, fun-sized surf. Wind patterns shift: N wind drops to 34.3%, and ideal wind rises to 12%. The autumnal transition brings more frequent cold fronts that can deliver clean offshore winds after passage. September is a fair month, offering improving consistency and quality as the North Atlantic reawakens.

Average Spot conditions at Sao Lourenco 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 Sao Lourenco 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 Sao Lourenco for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Sao Lourenco 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 Sao Lourenco.

Swell with good wind

Swell with good wind by size