Best Months To Surf Krui South Sumatra
The Indonesian surf seasons align with the Australian-Indonesian Monsoon cycle. Peak season coincides with the Southeast Monsoon April to September (Dry Season), off season with the Northwest Monsoon October to April (Wet Season). The 2 transitional periods March to May and September to November coincide with the shoulder seasons.
If you want to enjoy consistent swell and favourable wind directions on the South West Coast of mainland Sumatra plan your trip between May and October. All other months are risky. Could be OK, could be flat for 3 weeks but it's almost certain it will not be epic except for one week per month.
| Jan to Apr Off Season | January, February and March are off-season with rain, onshore winds and small confused swells. Traveling accross the world to surf the Krui area at this time of the year is being extremely optimistic. | |
| Apr to Jun Shoulder Season | Crowds are smaller in April but swell quality and consistency is still extremely poor. During April you can expect one decent swell a month with flat spells lasting 3 weeks. Conditions start improving in May. | |
| Jun to Sep Peak Season | During the southern hemisphere winter the Great Southern Ocean sends 1 large long lasting swell a week towards the Sumatran coast. Offshore winds make this the best time to score 1.8 mtr plus surf at Krui Left, The Peak, Ujung Bocur and Way Jambu. | |
| Sep to Nov Shoulder Season | Crowds start dropping off and rainy days begin increasing in late September. Risky months for a surf trip as the conditions could fall apart anytime. | |
| Nov to Jan Off Season | The worst of the rainy season. Swell size and consistency begins dropping off late September as the Southern Ocean winds down. By late November low pressure systems begin to develop south of the Sunda Strait. You can expect driving onshore winds and rain for weeks on end. Many tourist related businesses close down and the only surfers in the area are those that did not do their research or those that can't leave. |
South Sumatra is not Bali or the Mentawais
Surfers visiting the Krui area are often mystified when the surf in Bali, Java and the Mentawais is pumping on the same day the surf around Krui is small or even flat. A map of Indonesia, understanding the South Easterly trade winds and the predominat swell direction quickly removes this mystery.
South Westerly Facing Coastline
The coastline of South Sumatra faces south west with most of the major surfbreaks on the north side of headlands.
Predominant Swell Direction
The predominant swell direction is S to SW. A more southerly swell direction places many breaks in a swell shadow. This is why Krui Left, Krui Right, The Peak and Leftovers are often flat even during peak season and Ujung Bocur is often breaking wide and sectioning.
If you're looking out over a surbreak in the Krui area and wondering why the surf forecast is so unreliable ... guess no more. There are no 'real' wave bouys in the Indian Ocean any where near the South Sumatran Coastline. The swell is predicted by using global wave models with no inshore observational data fed back into the system. Basically you can't trust the surf forecast in this part of the world.
Trade Winds
The trade winds across Indonesia are produced by the Australian-Indonesian Monsoon system. The further west and north one goes the more the winds taper off in strength and become affected by other climate drivers.
Southeast Monsoon - April to October
During the Southeast Monsoon the winds are moderate and quite variable blowing north east to southerly (offshore to crossshore at most surf breaks).
Northeast Monsoon
During the Northeast Monsoon the winds are predominantly from the west (onshore at all surfbreaks).
El Niño-Southern Oscillation
Being one of the main drivers of the south easterly trade winds the El Niño-Southern Oscillation can have dramatic effects on the quality of surf in Sumatra. Conditions are particularly inconsistent during a La Niña phase when the Indian South West Monsoon and Australian-Indonesian monsoon converge over Sumatra.
El Niño
El Niño years usually produce the best surf with drier conditions and favourable trade winds. September can be magic on the South West Sumatra coast during an El Niño phase.
La Niña
La Niña years are more fickle and inconsistent with 20 - 40% wetter conditions and weaker trade winds. A shoulder season surf trip is far riskier during a La Niña phase.
The Bottom Line
Krui is not Bali, Java or the Mentawais so don't plan your Krui surf trip based on experiences in those locations. For the Krui area to light up requires SW swells and NE to SE winds. Those conditions occur more consistently during the peak season June to September. Shoulder months April, May, August and September can suffer 3 week long flat spells. La Niña years often produce poorer surf conditions.
