In the latest update ahead of 2026 New Year's celebrations, Indonesia's Meteorology, Climatology, and Geophysics Agency (BMKG) predicts light to moderate rain in most major cities on Wednesday, December 31, 2025. Heavy rain with thunder is possible in areas like Pekanbaru, Bandar Lampung, and Pontianak. The National Disaster Mitigation Agency (BNPB) urges local governments to verify disaster preparedness.
BMKG's forecast for December 31, 2025—building on prior warnings like those for December 23—anticipates light to moderate rain across most major Indonesian cities via its early warning system.
Sumatra: Light to moderate rain in Aceh, Medan, Tanjung Pinang, Padang, Jambi, Bengkulu, Palembang, and Pangkal Pinang; heavy rain with thunder in Pekanbaru and Bandar Lampung (per forecaster Yuyun).
Java: Light to moderate rain in Jakarta, Bandung, Semarang, Yogyakarta, and Surabaya; heavy rain with lightning possible in Serang.
Kalimantan: Heavy rain with lightning in Pontianak, Palangka Raya, and Banjarmasin; light to moderate in Tanjung Selor and Samarinda.
Bali and Nusa Tenggara: Thick clouds in Bali and Mataram; light rain in Kupang.
Sulawesi: Light to moderate rain in Mamuju, Palu, Makassar, Kendari, Manado, and Gorontalo.
Eastern Indonesia: Light to moderate rain in Ternate, Ambon, Sorong, Nabire, Jayawijaya, and Merauke; cloudy in Jayapura.
BMKG head Teuku Faisal Fathani stressed integrated weather data for hydrometeorological risks. BNPB's Abdul Muhari called for mitigation checks and noted weather modification collaborations with BMKG in high-risk areas.
This follows a December 30 forecast of heavier rain in some provinces; dynamic conditions warrant monitoring BMKG updates.
