Surf forecastStatisticsHistorical report

Grupuk seasonal overview

Best Surf Season (December - March)

The southern shores of Lombok come alive during the heart of the Indonesian wet season. From December through March, the monsoon trough shifts northward, allowing offshore winds from the north and northwest to prevail over 30-58% of the time. This window sees a steady supply of groundswell from the south and southwest, with average wave heights holding in the fun, rippable 1-1.5m range and periods consistently above 12 seconds. The combination of clean conditions and well-defined swell makes this the prime time for Grupuk.

Fair Surf Season (November & April)

The transitional months of November and April offer a mixed bag. Swell energy remains high, with periods often exceeding 13 seconds, but the wind patterns become less reliable. In November, offshore flow from the north and west appears only about 10% of the time, while onshore southerly and easterly winds dominate. April sees a sharp drop to 25% favorable winds as the southeast trade winds begin to strengthen. Still, when a light offshore breeze aligns with a SSW groundswell, you can score some of the smoothest waves of the year.

Low Surf Season (May - October)

The dry season transforms Grupuk into a wind-dominated challenge. From May through October, the southeast trades blow relentlessly, clocking in at 15-30 kph from the ESE and SE. Ideal offshore winds from the north are virtually absent (often less than 2% occurrence). While the swell actually peaks during these months – average heights climb to 1.6-1.8m with powerful, long-period energy (14+ seconds) – the almost constant onshore wind chops up the surface, making conditions predominantly messy and difficult. Only the most sheltered corners or fleeting windows of lighter wind offer rideable waves.

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Conditions at Grupuk in August

August: Trade Wind Hell

August continues the pattern of big, clean-lined swell ruined by onshore winds. Average height remains 1.8m with a 14.3s period. Swell is now heavily favoring SSW (70.8%), with a massive 19.5% of waves in the 2-2.5m category. This is some of the heaviest water of the year. But the wind is even more extreme – only 1% ideal. The ESE (45.9%) and SE (44.6%) trades blow at 20-30 kph, creating a constant white-capped mess. Paddling out is a battle, and wave quality is poor.

Average Spot conditions at Grupuk in August

Swell history for August

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

Wind history for August

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

Swell quality

Analyze the groundswell consistency at Grupuk 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 Grupuk for your next trip in August.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Grupuk 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 Grupuk.

Swell with good wind

Swell with good wind by size