Conditions at Sao Juliao in September
September: Autumn's First Whispers
September is a tale of transition at Sao Juliao. Average swell height climbs back to 1.6m (5.2ft), and the period lengthens to 10.5s, signaling the return of more organized groundswell. The direction spread is still summer-like - NW (36.0%) and NNW (34.4%) lead the way, with WNW (15.4%) providing a more favorable shoulder - but the energy is more consistent than July or August. Wind conditions improve only modestly, with NNW winds at 36.0% and N winds at 15.6%, but ideal offshore wind windows increase to about 12% of the time as synoptic systems begin to stir. These are often the best conditions of the month: the ocean is still warm (18.2°C), the air averages 19.8°C, and the first low-pressure systems of the season can deliver a clean, long-period W/WNW swell with east winds. Rainfall starts to tick up (0.95 mm/day), and the surf begins to feel alive again.
Average Spot conditions at Sao Juliao in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Sao Juliao 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 Juliao for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Sao Juliao 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 Juliao.