Surf forecastStatisticsHistorical report

Keramas seasonal overview

Best Surf Season (December - March)

The northwest monsoon takes hold, delivering a powerful combination of consistent, long-period S-SSW swell and predominantly offshore winds out of the northern quadrants. From December through March, Keramas comes alive. Average wave heights hover in the fun, rippable 0.8-1.0m range, but the 12-14s period gives them serious punch. This is when the iconic righthander is at its most groomed, offering smooth, hollow walls. The stats back it up: offshore wind frequency peaks at 64% in January and remains above 40% through March, creating clean, lined-up sets from morning to evening.

Fair Surf Season (April & November)

The transition months between monsoons introduce a pick-and-choose scenario. In April, the southeast trades start to strengthen, dropping offshore wind frequency to just 17%. However, the swell direction shifts more directly from the S-SSW, and average periods climb to nearly 14s. You can still find glassy windows early in the month before the afternoon sea breeze kicks in. November sees the return of northwesterly winds as the northwest monsoon builds, but the wind is still fickle – only 15% ideal. The swell, almost exclusively from the SSW, delivers clean, chest-to-head-high waves when the wind cooperates. It’s a month of patience rewarded.

Low Surf Season (May - October)

The southeast monsoon dominates from May through October, and for a SSE-facing reef, this is the cruellest period. Persistent onshore winds from the E-ESE-SE blow a steady 10-20kph, 50-70% of the time, chopping up even the most powerful swell. The wave heights actually peak during these months – averaging 1.0-1.1m with long 14s periods – but the wind-ruined surface makes most days unrideable. Offshore wind frequency plummets to between 1-5% from June to September. Only the occasional dawn patrol before the trades kick in, or a rare synoptic pattern that backs the wind to the north, will offer a window. This is the time to travel elsewhere or pack a groveler and hope for magic.

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Conditions at Keramas in September

September: Glimmers of Change

September shows the first subtle signs of the monsoon transition. Offshore wind frequency inches up to 2% – still terrible, but a hint of change. The wind distribution sees a slight increase in SSE winds (26.7%) and some SE (36.3%), still onshore. Swell remains solid: 1.1m average with a 14.1s period. The direction is overwhelmingly SSW (81.6%), with 51.3% in the 1-1.5m range. That’s a huge amount of chest-to-head-high, long-period swell. The afternoons remain blown out, but early mornings sometimes offer a brief glass-off before the trades kick. This is the month when the low season begins to loosen its grip.

Average Spot conditions at Keramas in September

Swell history for September

0 - 0.5
0.5 - 1
1 - 1.5
1.5 - 2.0
2.0 - 2.5
> 2.5 m

Wind history for September

0 - 10
10 - 20
20 - 30
30 - 40
40 - 50
> 50 km/h

Swell quality

Analyze the groundswell consistency at Keramas 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 Keramas for your next trip in September.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Keramas 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 Keramas.

Swell with good wind

Swell with good wind by size