BMKG Warns of High Waves off Southern Sumba on 16 September 2026

Labuan Bajo — — A weather bulletin for Wednesday, 16 September 2026, warned of waves between 2.5 and around 4 metres in the waters south of Sumba in East Nusa Tenggara, posing hazards for small vessels and coastal activities according to Indonesia’s meteorological agency BMKG and local media.

NTT Disway, citing BMKG data, reported that most districts in East Nusa Tenggara were expected to experience generally clear weather on land on 16 September, while BMKG issued a separate alert for high waves of 2.5–4 metres in the waters south of Sumba and urged coastal communities to pay close attention to sea conditions.

A separate report from RRI ende, based on information from BMKG’s Tenau Kupang Meteorological Station, noted that waves of 2.5–3 metres were forecast in the same southern Sumba waters, with the early warning in force from Wednesday, 16 September 2026 at 08:00 WITA until Thursday, 17 September 2026 at 08:00 WITA.

BMKG’s maritime forecast pages for the southern Sumba area also indicated potential high waves in mid-September, with modelled heights around 2.9 metres and advisory language for mariners to exercise caution and follow local authorities’ guidance.

Conditions on land and at sea

According to NTT Disway, BMKG’s general land forecast for 16 September 2026 expected mostly clear skies across a wide range of East Nusa Tenggara districts including East Sumba, West Sumba, Central Sumba and Southwest Sumba, with daytime temperatures in many areas reaching up to about 33°C.

The outlet emphasised that relatively clear weather over land did not eliminate risk at sea, noting BMKG’s warning for the waters south of Sumba where waves could reach 2.5–4 metres.

RRI’s reporting on the same period also described generally fair conditions, while underlining BMKG’s advice for fishermen and sea transport users to increase vigilance before operating in affected waters where wave heights of 2.5–3 metres could endanger navigation.

Implications for visitors and operators

Wave heights in the range of around 2.5–4 metres can be hazardous for small fishing boats, inter-island ferries and recreational craft, particularly in open waters without shelter or in areas with strong currents.

BMKG’s warnings, as relayed by NTT Disway and RRI, were directed at coastal communities, fishermen and sea transport operators, urging them to monitor updated marine forecasts and exercise caution when planning activities in the southern Sumba waters.

Visitors planning boat trips or surf sessions in southern Sumba are advised to check the latest official BMKG marine bulletins for the area, confirm conditions with local operators and harbour authorities, and heed any safety instructions or advisories in force on the day of travel.

Forecasts and validity periods can change from day to day, and the warnings cited for 16–17 September 2026 should not be used as a current guide for later dates such as 20 September 2026; travellers should rely on the most recent information issued by BMKG.

Related forecasts in September 2026

NTT Disway also reported that BMKG had maintained separate high-wave warnings for several East Nusa Tenggara waters on Monday, 14 September 2026, with heights of 2.5–4 metres while land conditions across many islands, including Sumba, were forecast to be mostly clear.

Earlier in September, RRI carried BMKG advisories for waves of 2.5–3.5 metres in parts of the Sumba Strait and southern Sumba waters, and later reports from RRI described continued high-wave threats in East Nusa Tenggara waters, including southern Sumba, through the period up to 20 September 2026.

These reports together show a pattern of generally clear weather over East Nusa Tenggara’s islands during parts of September 2026, combined with recurrent BMKG warnings for significant wave heights in surrounding seas, underlining the need for ongoing caution at sea even when conditions appear calm on shore.

Sources

• NTT Disway
• RRI Ende
• BMKG Maritim