Bali forecasters warn of waves up to four metres through October 30

In brief: On October 26, the Denpasar meteorological office forecast waves reaching four metres in waters south of Bali and in southern Lombok Strait from October 27 to 30. The forecast for Badung Strait, used by boats travelling to Nusa Penida, is up to 2.5 metres; no blanket suspension of sailings was announced in the warning.

The highest waves are forecast south of the island

Bali's regional meteorological office, BBMKG Region III, issued an updated outlook on October 26. A forecaster speaking to ANTARA said that seas in southern Bali waters and the southern part of Lombok Strait could reach four metres during the October 27–30 period. The figure describes a possible height across those sea areas, not the expected conditions at every harbour or beach.

Other stretches of water have a different forecast. Waves could reach 2.5 metres in Badung Strait, the southern part of Bali Strait and northern Lombok Strait. Wind patterns are contributing to the conditions: BBMKG expects speeds of up to 25 knots north of Bali and up to 20 knots to the south.

The latest statement also extends the forecast period beyond an earlier warning issued on October 23 for October 24–27. The new October 27–30 window is a further outlook, not evidence that four-metre waves have already been recorded throughout Bali's coastal waters.

Boat passengers should check the route, not just the headline

Badung Strait is relevant to travellers and residents taking boats from the Denpasar area to Nusa Penida. Its forecast ceiling of 2.5 metres is lower than the four-metre figure for more exposed southern waters, but it is still a potential concern for marine operations. BBMKG drew attention to conditions involving winds of around 21 knots and waves of 2.5 metres for ferry operators; it also warned fishing boats about winds above 15 knots and waves of 1.25 metres. These are safety warnings, not an announced legal closure of a route.

A rough-sea forecast does not establish whether a particular fast boat or ferry will operate. That decision depends on conditions closer to departure and instructions applying to the operator and port. Anyone with a time-sensitive crossing should seek the latest sailing information from the carrier and consult BMKG's updated marine forecasts, including its Info BMKG service.

For people who depend on island crossings as part of ordinary life, the relevant question is whether the whole journey remains workable, including the return leg and any onward connection. The warning covers several days, during which local conditions and operating decisions may change.