Conditions at Katahama in August
August: Longer Periods, Same Onshore Wind Bias
August is the peak of the NW Pacific typhoon season, and the statistics show it: the average wave period jumps to 9.2s, the highest of the year. Swell from the optimal quadrant is again plentiful, with SSE (21.1%), SE (18.2%), ESE (9.6%), and E (2.2%) totaling 51.1%, while S (19.8%) and SSW (17.8%) also add energy. The dominant swell heights are still in the 1-1.5m (3-5ft) range, but with these longer periods, even small waves pack a punch. The catch remains the wind: ENE (12.8%), E (13.5%), WSW (16.6%), and SW (11.9%) dominate, keeping the offshore W/NW share at a meager 9.1%. August surf is therefore a bin of opportunity: you have the swell power, but you need to pick off the moments when the wind flips to offshore - often in the early mornings or during the passage of a tropical cyclone. Water temps are warm at 26.7°C (a 3/2 wetsuit or just boardshorts for many), air averages 26.9°C, and precipitation drops to 5.02 mm/day as the rainy season has ended.
Average Spot conditions at Katahama in August
Swell history for August
Wind history for August
Swell quality
Analyze the groundswell consistency at Katahama during August. 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 Katahama for your next trip in August.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Katahama for August. 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 Katahama.