Conditions at Aterro in September
September: The First Taste of Autumn
September is the hinge month: average swell rises to 5-6ft (1.5-1.8m) and period stretches to 10.4 seconds, signalling the return of real ocean energy. NW (38.6%) and WNW (23.3%) pile in once again, with W (6.3%) and WSW (2.7%) giving Aterro's optimal window more than 70% of all swell direction - by far the best directional setup of the year.
Wind quality also improves. Ideal conditions reach 27%, as the strong summer NNW flow (29.2%) relaxes and E/SE (4.1%/2.6%) and S/SSW (5.4%/5.3%) days become more common. Air temps remain warm at 19.2°C, water is 16.8°C, and rain picks up to 1.92 mm/day. September surf can be surprisingly clean.
Average Spot conditions at Aterro in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Aterro 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 Aterro for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Aterro 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 Aterro.