Rainy Season in Indonesia to Start in Late 2026 As El Niño Persists: Agency

RRI.CO.ID, Jakarta – Indonesia’s Meteorology, Climatology, and Geophysical Agency (BMKG) said the country’s 2026 dry season will last longer than usual due to El Niño. The rainy season is forecast to begin toward the end of 2026, with a relatively shorter interval between its onset and peak.

Speaking at a press conference in Jakarta on Tuesday, September 22, 2026, the Agency's Deputy for Climatology, Ardhasena Sopaheluwakan, said 61.91 percent of Indonesia’s land area is currently experiencing or still experiencing the dry season. The agency also recorded more than 60 consecutive days without rain across 25 provinces, or around 65 percent of Indonesia’s 38 provinces.

"Both for this year’s El Niño episode and previous El Niño events, El Niño has always persisted until at least the end of the first quarter of the following year. So, the current episode is expected to persist at least until the end of the first quarter of 2027," he said, as monitored by RRI Voice of Indonesia.

Ardhasena said the rainy season is forecast to begin gradually between November and December 2026, with 61 percent of Indonesia’s land area expected to enter the rainy season later than usual. However, most parts of Indonesia are expected to enter the rainy season in November.

"The areas forecast to enter the rainy season in November comprise 185 seasonal zones, covering 24.66 percent of Indonesia’s land area," he said.

"Meanwhile, in December, it will cover 266 seasonal zones, or 17.3 percent of the country’s land area," he added.

Ardhasena said the peak of the rainy season is expected between December 2026 and February 2027, meaning the interval between the onset and peak of the rainy season will be relatively short. He warned of the potential for flooding and landslides as a result of the forecast.

"This means the rainy season will be shorter, the period between its onset and peak will also be relatively short, and the overall duration of the rainy season will be shorter. Therefore, we need to remain alert during periods of intense rainfall," he said.

Head of BMKG, Teuku Faisal Fathani, said he hoped the forecast would serve as a strategic basis for strengthening planning and improving preparedness. He also hoped the forecast would help sharpen mitigation and anticipatory measures across sectors affected by climate dynamics.

"More than just information, this forecast is expected to be translated into concrete action, adaptive policies, and faster, more targeted responses, both to address current needs and to build resilience in the face of changing climate conditions in the future," Faisal said.