The Asia-Pacific region is entering the final quarter of 2026 with several weather threats at once. Typhoons are still active in the western Pacific and floods have hit Bangkok. Smoke from forest fires covers parts of Sumatra. Over all of this sits an El Niño that forecasters expect to become very strong.

This article sets out the main events of the past week, the official outlook for the coming months and what the forecasts mean for Indonesia.

What happened this week

Typhoon Surigae passes south of Japan. Surigae, known in the Philippines as "Queenie", briefly reached super-typhoon strength east of Okinawa on 28 September, according to the US Joint Typhoon Warning Center, as reported by Nature World News. The storm left the Philippine area of responsibility on 27 September (Philstar).

By early on 1 October it was near Aogashima in the southern Izu Islands and losing organisation, and was expected to become an extratropical low within about a day, according to Japan Meteorological Agency reporting cited by News On Japan. Some airlines, including WestJet, offered flexibility for Narita flights, Open Jaw reported. Surigae followed Typhoon Dujuan, which left at least 12 people dead in Japan earlier in September, according to Watchers; later reports put the toll at 14.

Another typhoon forming. Typhoon No. 27 formed near the Mariana Islands on 1 October and is forecast to strengthen east of the Ogasawara Islands around 6–7 October, News On Japan reported.

Bangkok floods. Authorities declared a disaster zone across Bangkok on 26 September after close to 300mm of rain, with all 50 districts affected, Al Jazeera reported. The floods were easing by 30 September, The Star reported.

A new tropical depression. A tropical depression formed on 30 September about 3,300km east of Central Luzon, outside the Philippine area of responsibility.

Indonesian volcanoes. Mount Semeru in East Java erupted on the morning of 30 September, sending an ash column about 1,000 metres above the summit, CNBC Indonesia reported. Semeru remains at alert level III (Siaga). The exclusion zone runs 13km to the southeast along the Besuk Kobokan river and 5km around the summit. Mount Merapi in Central Java released three pyroclastic flows within minutes on the same afternoon, each travelling about 2km to the southwest, Okezone reported.

Haze in Sumatra. South Sumatra recorded 3,026 fire hotspots in 24 hours on 30 September. Fine-particle (PM2.5) readings in Palembang reached a level classed as hazardous, IDN Times reported. Earlier in September, ABC News reported that at least 200,000 hectares had burned and the ASEAN Specialised Meteorological Centre had raised its haze alert to the highest level, Level 3.

The big picture: a very strong El Niño

The main driver for the coming months is El Niño, the periodic warming of the central and eastern Pacific that tends to bring drier conditions to Indonesia, the Philippines and Australia.

The US Climate Prediction Center issued an El Niño advisory in September and gave a greater than 90% chance of a very strong event through the northern hemisphere fall and winter of 2026–27 (NOAA CPC). Its next update is due on 8 October.

The World Meteorological Organization said in early September that El Niño was almost certain to continue into early 2027. "This exceptional El Niño demands exceptional preparation and response," WMO Secretary-General Celeste Saulo said (WMO).

At the same time, BMKG says the Indian Ocean Dipole is likely heading toward a positive phase. In a positive phase, waters near Indonesia are cooler than those in the western Indian Ocean, which can further reduce rainfall over the archipelago.

What it means for Indonesia

BMKG, Indonesia's meteorology agency, says the combination will delay and shorten the 2026–27 rainy season. In its forecast of 22 September (BMKG), BMKG said:

Forecast Share of Indonesia's area
Rainy season starts later than normal 61.08%
Onset in November 24.66%
Onset in December 17.31%
Season shorter than normal 51.90%
Total rainfall within the normal range 69.76%

BMKG expects the peak of the rainy season between December 2026 and February 2027.

"The combination of El Niño and IOD occurring together worsens and prolongs the dry period across most of Indonesia, so the rainy season arrives late," BMKG head Teuku Faisal Fathani said (NDNews translation).

This creates two risks in sequence. First, a longer dry season extends the period of forest fires, haze and drought into October and November. Second, when the rains do arrive, heavy downpours on dry ground can still trigger floods and landslides. BMKG has recommended optimising drainage systems and preparing for both.

Even before the rainy season, BMKG issued warnings for 1 October, Kontan reported:

  • Heavy to very heavy rain: North Sumatra, West Sumatra, Bengkulu and Central Papua.
  • Moderate to heavy rain: 11 provinces, including Jakarta, Banten and West Java.
  • Waves of 2.5–4 metres: parts of the Indian Ocean west of Sumatra and south of Java, according to Bloomberg Technoz.

Disasters are already frequent this year. Indonesia's disaster agency, BNPB, recorded 1,730 disasters between 1 January and 7 September 2026, ANTARA reported. Most were weather-related:

  • 627 forest and land fires
  • 543 floods
  • 324 extreme-weather events
  • 105 landslides

Elsewhere in the region

  • Philippines: PAGASA expects one or two tropical cyclones a month from October to December, GMA News reported.
  • Australia: The spring bushfire outlook from the Australasian Fire and Emergency Service Authorities Council (AFAC) shows above-normal fire potential in parts of New South Wales, southeast Queensland, Tasmania and other states (AFAC).

The economic angle

Weather shocks feed directly into food prices. An adviser to Indonesia's agriculture minister said in August that he did not expect rice imports in 2026. The government has distributed more than 80,000 water pumps to farmers, and state logistics agency Bulog held 5.18 million tonnes of rice as of 2 July, ANTARA reported. A delayed planting season could test that plan. BMKG has advised farmers to plan planting carefully and use short-cycle rice varieties.

What to watch

  1. NOAA's El Niño update on 8 October, and whether the event is confirmed as very strong.
  2. Haze levels in Sumatra and Kalimantan, and any transboundary alerts for Malaysia and Singapore.
  3. The start of the rainy season in each region, and flood readiness in Jakarta and other cities.
  4. Further typhoons in the western Pacific and South China Sea.
  5. Rice prices and stocks as planting is delayed.
  6. Typhoon No. 27 as it strengthens east of Japan's Ogasawara Islands.

Readers in Indonesia should follow official warnings from BMKG and local disaster agencies (BPBD).

This article was researched with AI assistance and reviewed by the NDNews editorial team. It is based on official agency releases and media reports as of 1 October 2026. Conditions change quickly; always follow official warnings.