Thunders seasonal overview
Best Surf Season (May - September)
The heart of the dry season brings the Indian Ocean to life. Consistently strong southeast trade winds drive a relentless stream of long-period SSW groundswell that pours into the bay. Average wave heights climb to 1.5-1.7m with periods often exceeding 14 seconds. More importantly, the wind regime flips to a dominant easterly flow – blowing directly offshore from the land. This combination of powerful, directionally aligned swell and clean offshore winds creates the most consistent and high-quality surf of the year. Expect punchy, hollow right-handers off the reef when the swell lines up.
Fair Surf Season (April & October)
These transition months serve as the bookends of the prime season. While the monsoon winds are shifting, the Indian Ocean is still energized. Swell heights average around 1.3-1.5m with excellent periods (13-13.5s). The dominant swell direction remains SSW, delivering good waves. However, the wind reliability drops. You will experience more days of variable breezes and occasional onshore flows, but the windows of offshore easterlies still occur frequently enough to score fun, rippable waves. This is a solid shoulder season for uncrowded sessions.
Low Surf Season (November - March)
The northwest monsoon sets in, bringing a shift in both swell and wind patterns. Average swell heights drop to around 1.3m, and wave periods shorten slightly (12-13s). While the dominant swell direction remains favorable (SSW to SW), the quality suffers due to the atmospheric circulation. The wind direction swings predominantly from the northwest and west, blowing directly onshore across this west-southwest-facing beach. Ideal offshore easterlies become scarce, with wind being ideal only 26-32% of the time. Waves are more likely to be choppy, lumpy, and blown out. This season requires patience and luck to find a clean window between the trade winds and the monsoonal slop.
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Conditions at Thunders in September
September: The Last Gasp of the Trade Winds
The dry season is winding down. Average swell height holds at a solid 1.7m with period 14.1s. Swell is still excellent, coming from S (47.7%) and SSW (47.3%). Wind direction is still predominantly SE (37.6%) with ESE (12.9%), but the ideal wind percentage drops further to 44%. This means offshore conditions are still frequent, but the trades can be weaker and more intermittent. There are also increasing days of variable winds as the monsoon builds. The swell quality remains high, but you may need to check the forecast more carefully to catch the clean windows. September offers great waves with fewer crowds as the season winds down.
Average Spot conditions at Thunders in September
Swell history for September
Wind history for September
Swell quality
Analyze the groundswell consistency at Thunders 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 Thunders for your next trip in September.
Ground swell
Ground swell by size
Wind conditions
Evaluate the wind and swell alignment at Thunders 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 Thunders.
