September 14, 2025 | 07:21 pm
TEMPO.CO, Jakarta - Indonesia’s Meteorology, Climatology, and Geophysics Agency (BMKG) has officially declared the start of the rainy season, with several regions already transitioning from dry weather this September. Typically, the rainy season begins later in the year, but this time it has come earlier than expected.
Where the Rains Have Started
The first signs of the rainy season appeared in August across parts of Sumatra and Kalimantan. By September, the seasonal shift had spread southward and eastward. BMKG noted that this year’s dry season has been shorter and wetter compared to previous years.
“The majority of regions will enter the rainy season between September and November,” said BMKG Head Dwikorita Karnawati on Friday, September 12, 2025.
When Will the Peak Occur?
Sumatra & Kalimantan: November–December 2025
Java, Sulawesi, Maluku & Papua: January–February 2026
Dwikorita warned that because the peaks are staggered across regions, Indonesia may face prolonged risks of hydrometeorological disasters, such as floods, landslides, and strong winds, stretching over several months.
Bali Floods a Warning Sign
BMKG’s announcement followed a major flood in Bali on September 10, when rainfall reached 385.5 millimeters in a single day, more than double the threshold for extreme rain, which is 150 mm per day.
What’s Driving the Early Rains?
BMKG cited several climate patterns and weather systems fueling the heavy rainfall:
Equatorial Rossby wave, Kelvin wave, and Madden-Julian Oscillation (MJO), which are forecast to remain active for at least another week.
Tropical cyclone seed 93S forming in the Indian Ocean, west of Sumatra.
A cyclonic pattern detected near North Kalimantan.
Which Areas Should Be on Alert?
Between September 15–18, BMKG urged residents in the following regions to prepare for heavy rain, thunderstorms, and strong winds:
Central Java
East Java
West Kalimantan
West Sulawesi
South Sulawesi
Central Papua
Papua Highlands
South Papua
What This Means
Indonesia’s early rainy season underscores the growing unpredictability of climate patterns in the archipelago. While the rains provide relief after the dry season, they also heighten the risk of natural disasters across vulnerable regions.
Editor’s Choice: BMKG on Bali Floods: Extreme Rainfall, Environmental Factors Exacerbate Disaster
Click here to get the latest news updates from Tempo on Google News
BMKG on Bali Floods: Extreme Rainfall, Environmental Factors Exacerbate Disaster
1 hari lalu
BMKG found that Bali floods were also triggered by a mix of hydrometeorological factors and inadequate environmental and infrastructure conditions.
M7.4 Earthquake Hits Near Russia's East Coast; No Tsunami Threat for Indonesia
1 hari lalu
BMKG reported a tectonic earthquake with a magnitude of 7.4 that shook the eastern coast of Kamchatka, Russia, on Saturday, September 13, 202
Major Floods in Bali: What We Know About the Island's Extreme Weather
3 hari lalu
Bali has previously received an early weather warning from BMKG.
Floods Sweep Bali, Denpasar Yet to Declare Disaster Status
4 hari lalu
The Denpasar city government has not yet declared a disaster status after floods hit the city since early Wednesday morning.
BMKG Forecasts Heavier Rain Across Indonesia, Lists At-Risk Regions
4 hari lalu
The BMKG has issued an early warning for heavy rainfall, accompanied by thunderstorms and strong winds, for several areas.
These Are Bosscha Observatory's Total Lunar Eclipse Reports in Indonesia
6 hari lalu
Observatorium Bosscha operates a network of 22 observation points, ensuring clear observations of the lunar eclipse even in cloudy conditions.
Micro-Earthquake Shakes Ciater Area in Subang, Indonesia
6 hari lalu
The micro-earthquake also occurred in Konawe, South Konawe, and Kendari more strongly today. Check out the data from BMKG.
5 Essential Tips for Watching Tonight's Total Lunar Eclipse
6 hari lalu
The total lunar eclipse lasts for about 1 hour 22 minutes out of the whole process, which takes more than 5 hours. This phenomenon can be observed in Indonesia, weather permitting.
Total Lunar Eclipse Observable from Indonesia, Here Are the Phases and Durations
7 hari lalu
Indonesia's Meteorology Agency (BMKG) predicts that the lunar eclipse will last for 5 hours 29 minutes 48 seconds, covering all of its phases.
BMKG Forecasts Thunderstorms in Greater Jakarta Today
9 hari lalu
According to BMKG weather forecast, rain, and possible thunderstorms today. This comes as a different condition after several days of scorching heat.
