Defara Dhanya, Jakarta – It turns out there is a scientific reason behind the prolonged rainfall in most regions of Indonesia throughout 2025. Ardhasena Sopaheluwakan, Deputy of Climatology at the Meteorology, Climatology, and Geophysics Agency (BMKG), explained that Indonesia's climate is influenced by local sea dynamics and the regularly monitored Pacific Ocean to the east and Indian Ocean to the west.

Indonesia is currently experiencing a unique situation involving a weak La Nina and a negative Indian Ocean Dipole (IOD). "In the Pacific Ocean, there is a weak La Nina with a large index of -0.77 at the end of last November, marked by the cooling of the Central Pacific region," Ardhasena said in the Climate Outlook 2026 broadcast online on Tuesday, December 23, 2025.

Meanwhile, he continued, a negative IOD phenomenon with an index of -0.83 was detected in the western Indian Ocean. This condition causes the water in this area to be colder than in the eastern area near Indonesia. "This background condition is what has caused the recent high rainfall in Indonesia," he explained.

According to Ardhasena, Indonesia's geographical position, surrounded by seas with colder temperatures in the west and east, as well as very warm temperatures in local waters, also contributes to the formation of rainfall. "The anomaly of sea surface temperatures is more than 2 degrees Celsius, so we release a lot of heat," he said. "We also experience a lot of rain."

He stated that the warm sea conditions make Indonesia play a crucial role in the global climate system. "With a geographical configuration that fulfills many needs, Indonesia acts as a steam engine that helps regulate the world's climate conditions."

Source: https://en.tempo.co/read/2075641/bmkg-outlines-causes-of-indonesias-continuous-rainfall-this-yea