Conditions at Tywyn in September
September: The First Taste of Autumn
September is when the North Atlantic starts to shake off its summer slumber. Average wave height lifts to 2.3ft (0.7m) and the period stretches slightly to 6.8s. WSW remains the engine room at 36.5 percent, with SW at 21.3 percent and W at 10.5 percent. More importantly, the bigger size classes begin to reappear: roughly 6 percent of observations now reach 5ft (1.5m) or more, and the 1-1.5m (3-5ft) category is noticeably better represented than in the summer months. Early autumn lows and the first strong cold fronts can also throw in some longer-period groundswell, especially if an ex-hurricane tracks up the Atlantic.
Despite the energy increase, ideal wind conditions are still limited to 6 percent. Onshore westerly and southwesterly winds continue to dominate at around 37 percent, and the average period of 6.8s means the swell can still look disorganized. The tradeoff is weather: air temperatures remain pleasant at 14.5°C, water warmth persists at 16.4°C, and precipitation averages 2.88 mm/day. A late-summer longboard session or an early-autumn, wind-swell pump are both on the menu.
Average Spot conditions at Tywyn in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Tywyn 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 Tywyn for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Tywyn 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 Tywyn.