The Meteorology, Climatology, and Geophysics Agency (BMKG) has predicted that the rainy season will arrive earlier than normal this year. BMKG reported that some regions in Indonesia have already entered the rainy season since August, and the coverage is expected to expand between September and November. This condition may increase the risk of hydrometeorological disasters such as floods, landslides, and strong winds.
In response to BMKG’s forecast, Dr. Hatma Suryatmojo, a hydrology and watershed management expert at the Faculty of Forestry, Universitas Gadjah Mada (Forestry UGM), emphasized the importance of community and local government preparedness in anticipating changes in seasonal patterns.
He highlighted the need for both structural and non-structural mitigation efforts.
Flood control infrastructure, such as retention basins, river normalization, and improvements to urban drainage systems, should be accelerated.
“In landslide-prone areas, terracing and the construction of retaining walls are necessary. In addition, nature-based solutions such as upstream watershed reforestation are crucial for long-term resilience,” said Dr. Suryatmojo on Tuesday, Sep. 16, 2025, at the UGM campus.
Dr. Mayong, as he is familiarly known, explained that the earlier arrival of the rainy season cannot be separated from the El Niño-Southern Oscillation (ENSO), which was in a neutral phase last August.
At the same time, the Indian Ocean Dipole (IOD) was recorded in a negative phase, resulting in the Indian Ocean supplying additional water vapor to the western part of Indonesia.
Coupled with sea surface temperatures that were approximately 0.42°C above average, these factors triggered the formation of more intense rain clouds.
Moreover, global climate change also plays a role in intensifying rainfall and making seasonal patterns increasingly difficult to predict.
Data show that 294 seasonal zones, or around 42% of Indonesia’s territory, experienced an earlier onset of the rainy season compared to the norm.
According to him, the greatest challenge of the early rainy season is the heightened risk of flash floods and landslides.
This is exacerbated by deforestation and land degradation in many watersheds, which worsen flooding and landslides.
“Under natural conditions, forests and vegetation absorb rainwater and reduce erosion. However, when forest cover diminishes, rainwater is directly discharged as surface runoff,” the expert explained.
On the other hand, he also underlined the importance of research, technology, and cross-sector collaboration.
The application of artificial intelligence (AI) by BMKG to improve the accuracy of rainfall forecasts down to the regency level is seen as a positive step.
GIS-based vulnerability maps can also assist local governments in identifying disaster-critical points.
“With strong collaboration and high public awareness, the impact of hydrometeorological disasters can hopefully be minimized,” he said.
He further expressed hope that the government would mainstream climate change adaptation and disaster risk reduction into development policies.
Strengthening environmental regulations, enforcing stricter spatial planning, and investing in green infrastructure should be prioritized.
He stressed that national preparedness will not succeed without strong public awareness.
“Communities must understand that today’s climate patterns differ from the past, making mental readiness and adaptive attitudes very important. Climate change education needs to be intensified, from schools to farmer groups, so that the public knows what steps to take when signs of extreme weather appear,” he concluded.
Author: Kezia Dwina Nathania
Editor: Gusti Grehenson
Post-editor: Lintang Andwyna
Illustration: Freepik