Foz seasonal overview
Best Surf Season (October - March)
The North Atlantic delivers its heaviest punches during the winter half-year, with extratropical cyclones churning out consistent, long-period NW swell. Foz's northeast-facing orientation is perfectly aligned to capture these waves, and with average swell heights hovering between 1.3m and 1.7m and periods exceeding 11 seconds, the lineup is often firing. Crucially, the percentage of offshore wind (from the SW quadrant) peaks during these months, reaching over 40% from October through February. This combination of powerful groundswell and favorable wind makes October through March the premier window for quality surf at Foz. Expect pumping, rippable waves with the potential for XXL days when the storm track aligns.
Fair Surf Season (April & September)
These transitional months offer a mixed bag. The average swell size drops to around 1.1-1.3m, and periods shorten into the 10-second range, indicating a shift from winter groundswell to more windswell dominant patterns. However, the NW quadrant still provides a good chunk of the energy, and occasional late-season or early-autumn storms can deliver fun, solid waves. Offshore wind frequencies sit around 32%, so picking the right day is key. April sees increasing easterly winds that can clean things up, while September holds onto summer warmth with a rising swell trend.
Low Surf Season (May - August)
Summer brings a dramatic drop in surf size and energy. Average swell heights fall below 1m, and periods shorten to 8-9 seconds, resulting in mostly weak, wind-driven chop. The dominant swell directions remain NW and NNW, but the energy is simply not there. Furthermore, offshore wind percentages plummet to the 25-26% range, as the region comes under the influence of the Azores High, driving northeasterly trade winds that blow onshore or cross-shore at Foz. While the occasional small west swell might sneak in, conditions are generally poor for serious surfing. This is the time to focus on other activities, though dawn patrol glass-offs can still yield grovel-worthy waves on the best days.
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Conditions at Foz in September
September: The Autumn Awakening
September sees the first signs of autumn as the ocean begins to stir. Average swell height rises to 1.1m and period to 10.1s, indicating a return of more energetic groundswell. NW (35.2%) and NNW (34.5%) quadrants still dominate, and the percentage of waves in the 1-1.5m range increases. Wind becomes slightly more favorable with 32% offshore. SSW (9.6%) and SW (9.8%) winds are more present than in summer, and the NE winds weaken. However, the wind is still variable. September can deliver some solid late-season swells from early autumn storms, and with water temps still warm, it's a prime time for a swell chase. The first decent pumping days of the season often occur this month.
Average Spot conditions at Foz in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Foz 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 Foz for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Foz 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 Foz.
