BMKG Forecasts 1.6m Flores Sea Waves in September Dry-Season Window

Labuan Bajo — Waves in the Flores Sea were forecast to reach up to 1.6 metres in mid-September 2026, underlining that the dry season around Labuan Bajo does not guarantee uniformly calm sailing conditions for Komodo routes according to Indonesia’s meteorological agency BMKG.

BMKG’s marine forecast for the Flores Sea listed a valid period from 10 September 2026 at 00.00 to 13 September 2026 at 00.00, with a detailed table showing thick cloud cover, easterly winds of about 13–14 knots, short-term gusts up to 29 knots and significant wave heights rising to 1.6 metres during the afternoon of 11 September 2026. The agency classified conditions in the Flores Sea as sedang, or moderate, and noted a potential for moderate waves of around 1.5 metres in the area.

Under BMKG’s maritime scale, moderate seas generally refer to wave heights between 1.25 and 2.5 metres, above the low category of 0.5 to 1.25 metres but below the rough and very rough classifications used for higher swells in Indonesian waters. A separate BMKG shipping bulletin for the larger Metarea XI region listed the Flores Sea with easterly winds of 5–17 knots and moderate sea conditions, using the same height bands for each sea state category.

The forecast applies to the broader Flores Sea, not to every individual channel, jetty or route inside Komodo National Park. That distinction matters operationally because conditions can be more sheltered inside the harbour at Labuan Bajo while becoming rougher in exposed straits where currents from surrounding basins meet.

September is drier, not risk-free

Local port guidance describes Labuan Bajo as having two main seasons rather than four. A generally drier period runs roughly from April to October, with calmer seas and better underwater visibility, while a wetter season from November through March brings stronger west-monsoon winds and a higher chance of weather-related delays in the Flores Sea and the nearby Sape Strait according to Bajo Port.

Bajo Port notes that September sits late in the dry season and is commonly associated with settled weather, relatively low rainfall and more predictable day-to-day conditions, making it a favoured month for sea travel. A local tourism guide similarly describes a dry, clear pattern from May to October, with September highlighted as a particularly attractive month and November marked as a transition period when rain begins to return.

These seasonal patterns change probabilities rather than determine conditions on a specific date. Bajo Port cautions that rough seas can still develop during drier months and that calm days can occur in the wet season, especially outside the January–February core when rain and wind are most persistent.

Reading practical indicators

The practical variables for a boat trip are wind strength and direction, wave height and currents rather than air temperature alone. BMKG’s detailed Flores Sea forecast for 10–13 September recorded easterly winds in the 13–15 knot range, short-term gusts reaching 24–29 knots and currents generally running toward the southwest at around 1.2–1.3 knots, alongside wave heights that increased from about 1.3 metres to 1.6 metres as the forecast period progressed.

BMKG’s high-wave warning page for mid-September 2026 also highlighted elevated wind speeds over several eastern Indonesian seas, including the Flores Sea and waters around Komodo National Park, with maximum winds reaching around 25 knots. A separate forecast for the wider Nusa Tenggara Timur seas noted moderate conditions with similar wind ranges in the Flores Sea.

Route selection and exposure matter as much as the headline forecast. Bajo Port explains that Komodo itineraries pass through a mix of sheltered bays and more exposed channels, and that currents in narrow straits can be stronger and less predictable where different water masses meet. These currents influence both crossing decisions and the timing of dives and snorkelling inside the park.

Clearance and traveller checks

Operational decisions are based on current conditions and official advisories rather than the month label. Bajo Port notes that the harbourmaster, or Syahbandar, assesses real-time weather and BMKG updates before issuing sailing clearance, and that licensed operators are expected to comply with those instructions.

Travellers are advised to ask operators for the latest forecast covering their full route, not only the weather in town, and to confirm whether the vessel has obtained sailing clearance and what happens if conditions prevent departure. Bajo Port adds that cancellation and rebooking policies differ among companies; common arrangements may include moving trips to the next workable window or offering partial refunds when itineraries are shortened, so passengers should understand the specific terms before paying a deposit.

Local marina guidance similarly emphasises planning around the April–October dry season for more reliable sailing, while acknowledging that November–March brings increased wind and rainfall and therefore a greater need for flexibility. For visitors, building a buffer day into travel plans, especially in September shoulder periods, can help absorb weather-related delays even when overall conditions remain within BMKG’s moderate range.

Sources

• BMKG Maritime — Prakiraan Cuaca Perairan Laut Flores
• Bajo Port — Weather and Sea Conditions at Labuan Bajo Port
• Labuan Bajo Tourism — Best Time to Visit Labuan Bajo: A Local's Honest Guide
• Labuan Bajo Marina — Weather and seasonal considerations for Labuan Bajo Marina
• Kupi Travel — Labuan Bajo Weather – Forecast, Seasons & Packing