BMKG Warns of 4-Metre Waves Off Southern Bali Through 19 September

Denpasar — Indonesia’s Meteorology, Climatology and Geophysics Agency (BMKG) warned of waves as high as 2.5 to 4 metres in the waters south of Bali and the southern Lombok Strait from 16 to 19 September 2026, according to BMKG Regional Center III in Denpasar and local reporting that cited its marine bulletin.

BMKG’s Bali forecast page for 16 September also flagged a separate early warning for increased wind and wave heights that could reach 2 metres or more in the southern Bali waters, the southern Bali Strait, Badung Strait and Lombok Strait. The agency’s marine forecast for the southern Bali Strait listed wave heights around 2 to 2.7 metres during the day, underscoring changing conditions across nearby waters.

Areas at risk

The highest waves were forecast for the waters south of Bali and the southern section of the Lombok Strait. Other waters named in BMKG’s Bali forecast included the southern Bali Strait, Badung Strait and northern Lombok Strait, where waves were lower but still potentially hazardous for small vessels.

Local coverage based on BMKG’s bulletin said the warning was relevant to ferries, fishing boats, barges and marine tourism activities in exposed areas. BMKG’s general safety guidance also links hazardous conditions for fishing boats, barges and ferries to rising wind speeds and wave heights in the ranges cited by the agency.

What BMKG said

BMKG’s Bali forecast for 16 September listed east-to-southeast winds at 4-40 km/h and wave heights of 0.75 to 3.0 metres in the southern Bali waters, with 0.5 to 1.25 metres in northern Bali waters. The same page included an early warning for higher wind and wave conditions in the southern sea lanes around Bali.

In the marine bulletin, BMKG classified wave heights of 2.5 to 4 metres as rough sea conditions. The agency’s shipping forecast also said conditions in the Indian Ocean south of Bali were expected to be rough, with easterly to southeasterly winds affecting surrounding waters.

Travel and marine operations

Travellers using ferries or fast boats were advised to check with operators before departure, as conditions in the straits can shift quickly. Fishermen, charter crews and water-sports businesses were urged to assess conditions in their own operating areas rather than rely only on the appearance of calm water near shore.

The warning covered a busy stretch of coastline that includes southern Jembrana, southern Tabanan, Badung, Denpasar, Gianyar and southern Klungkung. BMKG did not identify specific beaches or issue beach-by-beach closure orders in the material reviewed.

Sources

• BMKG Regional Center III Denpasar
• IDN Times Bali