Conditions at Guincho in September
September: First True Groundswell of Autumn
September is the month when Guincho starts waking up. Average swell climbs back to 5-6ft (1.5-1.8m), the period stretches to 10.5s, and the directional mix shifts from pure NNW windswell back toward NW and WNW groundswell. There are already days with proper head-high, lined-up surf, especially when the first genuine low-pressure systems push into the northern Atlantic. The wind remains summer-like - NNW blows 42% of the time, and the offshore percentage only reaches 11% - so the formula is unchanged: dawn patrol is your friend. Water stays warm at 18.6°C, air temps average 20°C, and rain is still mostly absent. As the Atlantic begins to stir, long-period swells from W-WNW can appear on the charts, and when an easterly land breeze sits on top, September at Guincho can feel a lot like the start of the real season.
Average Spot conditions at Guincho in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Guincho 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 Guincho for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Guincho 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 Guincho.