Conditions at Ribeira d'Ilhas in September
September: Autumn Stirrings and Warm-Water Groundswell
September marks the transition back to real surf. The Azores High begins to weaken, and the first deep North Atlantic lows start to send longer-period energy toward Portugal. Average surf height climbs to 1.6m (5.2ft), while the average period lifts noticeably to 10.5s - the first sign that winter is on the way. Swell is still strongly NW (36.0%) and NNW (34.4%), with WNW at 15.4%, but there is more W and SW energy mixed in than in midsummer. The wind becomes a little more cooperative: ideal conditions rise to 22%, though NNW still leads at 36.0% and offshore quadrant winds remain a modest 5% of the raw wind distribution. Water temps sit at their warmest around 18.2°C, air averages 19.8°C, and precipitation starts to increase slightly to 0.95mm/day. When an early autumn low aligns with a NE offshore, Ribeira lights up with warm, glassy, 4-6ft (1.2-1.8m) groundswell - a very good time to be there.
Average Spot conditions at Ribeira d'Ilhas in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Ribeira d'Ilhas 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 Ribeira d'Ilhas for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Ribeira d'Ilhas 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 Ribeira d'Ilhas.