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 December

December: Building Toward Prime

December signals the arrival of the wet season. Swell heights drop slightly to an average of 1.3m with a 12.7s period. Swell directions are more spread: SSW (62.8%) and SW (36.1%), offering a nice mix of lines. The wind picture improves dramatically, with 33% ideal conditions. Strong northwesterly winds (WNW 10.5%, W 20.4%) blow at 10-20 kph, creating offshore perfection for the south-facing beach. The consistent groundswell and increasingly clean conditions make December a fantastic month to start the peak season.

Average Spot conditions at Grupuk in December

Swell history for December

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

Wind history for December

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

Swell quality

Analyze the groundswell consistency at Grupuk during December. 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 December.

Ground swell

Ground swell by size

Wind conditions

Evaluate the wind and swell alignment at Grupuk for December. 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