Conditions at Shonan in September
September: Typhoon Swell Meets the First Offshore North Winds
September is where the season starts to turn. The average period is a solid 9.0s and the average height 2.6ft (0.8m); more importantly, the wind rose begins to flip back toward offshore as autumn fronts start pushing down from the north. NNE (25.0%) and N (7.7%) provide clean offshore windows, NE adds cross-shore texture, and the ideal-wind percentage rises to 18%. The swell still carries late-summer warmth: S (21.0%), SSE (20.3%), SE (17.0%) and SSW (12.7%). Typhoons and decaying tropical storms are a major factor, and they can toss 3-5ft (1-1.5m) or even larger south/southeast swell into Sagami Bay. The catch is rainfall -- precipitation peaks at 7.15mm/day as tropical moisture gets slung into the region. Water temperature is 25.4C and air averages 22.0C. When the post-typhoon skies clear and the wind goes offshore, September can produce some of the best, most powerful waves of the year.
Average Spot conditions at Shonan in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Shonan 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 Shonan for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Shonan 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 Shonan.