Conditions at Grindavik in September
September: Autumn Awakens
September is the true transition back to real surf. Average swell height climbs to 1.5m (4.9ft), and the average period increases to 9.4s. The S-SSW-SW quadrant remains the main source of waves, with SW at 21.8%, SSW at 15.1%, S at 9.5% and WSW at 11.9%. There is now a solid chunk of 1.5-2.5m (5-8ft) groundswell mixed in, giving Grindavik more power than the summer months. Ideal offshore wind drops slightly to 20%, but NNW and N winds are still common, and the cleaner autumn air begins to arrive. The Icelandic Low is re-engaging, and the first proper North Atlantic lows can produce punchy, well-ordered waves on the south-facing breaks. Air temps average 8.3°C, water temps settle at 10.4°C, and rainfall increases to 4.93mm/day. September is a genuine shoulder month with both size and quality on offer.
Average Spot conditions at Grindavik in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Grindavik 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 Grindavik for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Grindavik 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 Grindavik.