Kabar Gemerlap - An in-depth analysis by the Badan Meteorologi, Klimatologi, dan Geofisika (BMKG) indicates that the 2026/2027 rainy season will arrive later than usual across most of Indonesia. This delay is attributed to the exceptionally strong El Niño phenomenon and a positive Indian Ocean Dipole (IOD), both of which are expected to suppress rainfall in key regions.
According to BMKG's latest research, 529 out of 867 ZOMs (Zona Musim) — covering 61.08% of Indonesia's landmass — are projected to experience a delayed transition to the rainy season compared to historical norms. Meanwhile, only 26 ZOMs (2.15% of landmass) will follow the typical seasonal pattern.
The analysis highlights regional variations: 185 ZOMs (24.66% of landmass) are expected to enter the rainy season in November 2026, with northern Sumatra leading the transition. These areas include parts of Sumatra, Java, Kalimantan, Bali, NTB, NTT, Sulawesi, Maluku, and Papua.
Further, 266 ZOMs (17.31% of landmass) are projected to begin the rainy season in December 2026, encompassing regions like Lampung, southern Java, Kalimantan Selatan, and parts of Papua.
BMKG emphasizes that local variations in rainfall onset are influenced by complex interactions between El Niño and IOD. The study warns that stakeholders in agriculture, water management, and disaster preparedness must monitor these shifts closely, as the delayed onset could disrupt crop cycles and flood mitigation efforts.
Regional Breakdown
- November 2026: Northern Sumatra, parts of Java, Kalimantan, Bali, NTB, NTT, Sulawesi, Maluku, and northern Papua.
- December 2026: Lampung, major parts of Java, Kalimantan Selatan, Bali, NTB, NTT, Sulawesi, Maluku, and southern Papua.
BMKG's findings underscore the need for localized climate adaptation strategies, particularly in regions where the rainy season's timing deviates significantly from historical averages.