Conditions at El Frontan in September
September: First Signs of Autumn, Still Sea-Sick
September is a transitional month in the Bay of Biscay. Average swell height drops to around 4ft (1.2m), the smallest of the year, but the period climbs back to 10.1s, hinting at the approaching autumnal groundswell. Direction is again favourable: N 29.2%, NNE 32.6%, NNW 28.3% and NW 6.8% combine for 97% of the energy. Some of those early-season Atlantic lows are beginning to send longer-period pulses, but the overall size is limited.
Wind quality remains poor. Ideal offshore wind occurs just 5% of the time, with NNE at 41.1% and NE at 32.6% dominating. This keeps the surface lumpy and often rules out the best of the incoming swells. Water temperature peaks at 23.4°C, air at 22.8°C, and rainfall remains low at 0.33mm/day. As the high pressure weakens later in the month, the first proper offshore windows start to appear, marking the slow return of quality at El Frontan.
Average Spot conditions at El Frontan in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at El Frontan 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 El Frontan for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at El Frontan 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 El Frontan.