Conditions at Inamuragasaki in September
September: The Autumn Switch - Typhoon Swells and Returning Offshore Winds
September is a true transition month. Average swell remains 0.8m (2.6ft), but the period stays long at 9.0s, meaning the water has serious energy even if the heights aren't extreme. Swell direction is still south-heavy - SSE (20.3%), S (21.0%) and SSW (12.7%) - while SW drops off, but the wind balance begins to shift back in the surfer's favour. Offshore N/NNE/NE/NNW flow returns to about 50% of the time, with NNE (25.0%) and NE (14.0%) leading the way. Onshore winds fall to about 33%, and ideal conditions rise to 18%. Typhoons are the wildcard: a late-season storm can deliver pumping 1.5-2.5m (4.9-8.2ft) swell with clean offshore winds if the track and timing align. Water temperature remains warm at 25.4°C, air drops slightly to 22.0°C, and precipitation peaks at 7.15 mm/day - the wettest month. This is when Inamuragasaki starts to get genuinely good again.
Average Spot conditions at Inamuragasaki in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Inamuragasaki 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 Inamuragasaki for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Inamuragasaki 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 Inamuragasaki.