Conditions at Rossnowlagh in September
September: The Atlantic Reawakens
September is the gateway back to serious surf. The average swell height lifts to 1.1m (3-4ft) and the average period climbs back above 10s to 10.2s, signaling the return of more organized groundswell. WNW is again the dominant swell direction at 34.6%, with W at 19.5%, NW at 17.5%, and NNW at 10.8%. More importantly, the height distribution shows a real increase in 1-1.5m waves and a solid percentage of 1.5-2m lines from the W/WNW window. Wind quality is still fickle: WSW at 10.9%, SW at 9.3%, W at 9.2%, and SSW at 9.1% keep onshore winds frequent, and ideal conditions sit at only 21%. Still, the autumn storm track is warming up, and when the E/ESE offshore winds appear, Rossnowlagh can suddenly be firing again. Water temp is still pleasant at 15.3°C, with air temps around 12.4°C and rain at 3.5mm/day.
Average Spot conditions at Rossnowlagh in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Rossnowlagh 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 Rossnowlagh for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Rossnowlagh 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 Rossnowlagh.