Very Strong El Niño: BMKG Issues Latest Warnings and Predictions

The Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has confirmed that a very strong El Niño climate anomaly is currently occurring. Furthermore, the Indian Ocean Dipole (IOD) index has also been confirmed as positive.

According to the Atmospheric Dynamics Analysis for the third ten-day period (Dasarian III) of September 2026 released by BMKG on Monday (5/10/2026), monitoring results show a decadal IOD index of +0.99 (September: +0.72). Meanwhile, the Sea Surface Temperature (SST) anomaly in the Nino3.4 region for this period was recorded at +3.44. The three-month ENSO index (July-August-September) stands at +2.70. BMKG stated that these conditions indicate an El Niño event of very high intensity.

The combination of these two phenomena is causing the dry season in Indonesia to be extremely hot, with a significant reduction in rainfall. Previously, on 22 September 2026, BMKG announced that the simultaneous occurrence of these phenomena would exacerbate and extend the drought period in most parts of Indonesia. Consequently, the 2026/2027 rainy season is predicted to arrive late and feature a shorter duration.

According to BMKG, as of the third ten-day period of September 2026, approximately 5.7% of Indonesia’s territory, or 40 Seasonal Zones (ZOM), has entered the rainy season. These areas include parts of Jambi, South Sumatra, Banten, West Java, West Kalimantan, East Kalimantan, West Sulawesi, Maluku, Southwest Papua, West Papua, Papua, and Highland Papua.

For the first to third ten-day periods of October 202long, BMKG predicts that rainfall will generally fall within the Low-Medium criteria (0-150 mm per ten-day period). However, BMKG has issued a ‘Warning’ (Waspada) for high rainfall in several regencies and cities within the provinces of Aceh, North Sumatra, West Sumatra, and Bengkulu, effective for the first ten-day period of October 2026. Currently, there are no ‘Alert’ (Siaga) or ‘Danger’ (Awas) level warnings for high rainfall potential for the first ten-day period of October 2026.

Regarding meteorological drought, BMKG has issued early warnings for the first ten-day period of October 2026 as follows:

• Warning (Waspada): Several regencies in West Java, Central Java, Bali, South Kalimantan, Central Kalimantan, East Kalimantan, Central Sulawesi, Maluku, West Papua, and South Papua.

• Alert (Siaga): Several regencies in Bangka Belitung Islands, Lampung, West Java, Central Java, East Nusa Tenggara, South Kalimantan, Central Kalimantan, East Kalimantan, South Sulawesi, Central Sulawesi, Southeast Sulawesi, Gorontalo, North Sulawesi, North Maluku, and South Papua.

• Danger (Awas): Several regencies in South Sumatra, Bangka Belitung Islands, Lampung, Banten, DKI Jakarta, West Java, Central Java, DI Yogyakarta, East Java, Bali, West Nusa Tenggara, East Nusa Tenggara, West Kalimantan, South Kalimantan, Central Kalimantan, East Kalimantan, West Sulawesi, South Sulawesi, Central Sulawesi, Southeast Sulawesi, Gorontalo, North Sulawesi, Maluku, North Maluku, and South Papua.

Furthermore, monitoring of ‘No Rain Days’ (Hari Tanpa Hujan - HTH) updated for the third ten-day period of September 2026 shows that thousands of points across Indonesia are experiencing extreme long-duration dry spells, with no rainfall for more than 60 consecutive days. BMKG noted that 250 points are experiencing long dry spells, 313 points are experiencing very long dry spells, and 1,869 points are experiencing extreme long dry spells. The longest dry spell, lasting 151 days, was reported at the BPP (Agricultural Extension Institute) Pajangan rain gauge in Bantul Regency, DI Yogyakarta.