BMKG Forecasts Heavy Rain Across Indonesia on 18 June 2026
The Meteorology, Climatology and Geophysics Agency (BMKG) has released its weather forecast for Indonesia on 18 June 2026, along with an early warning regarding the potential for extreme weather in several regions. This is triggered by the formation of a cyclonic circulation in the Pacific Ocean north of West Papua, which is causing significant convergence areas.
BMKG forecaster Alya Sausan explained that the circulation system is detected stretching from the Pacific Ocean north of West Papua, along the northern coast of Papua, to the northeastern Pacific waters of Papua. This condition creates areas of wind convergence and confluence that extend to the South China Sea, Sulawesi, and northern Kalimantan.
The cyclonic circulation north of Papua is triggering massive rain cloud growth. Regions located in the convergence path, such as Papua Pegunungan and North Kalimantan, have the potential to experience increased rainfall intensity in the coming period.
For the western part of Indonesia, BMKG has asked residents in Tanjung Selor to be alert for the potential of moderate-intensity rain. Meanwhile, light rain is forecast to fall over most major cities in Sumatra and Kalimantan, including Banda Aceh, Medan, Pekanbaru, Palembang, Banjarmasin, and Pontianak.
On Java Island, weather conditions tend to be more stable. Major cities such as Jakarta, Yogyakarta, Surabaya, Semarang, and Serang are predicted to be dominated by partly cloudy to overcast skies. Based on validated data from the server on 18 June 2026 at 08:10 WIB, the temperature in Jakarta (Gambir) was recorded at 29 °C with clear conditions, while Bandung (Citarum) was at 23 °C.
Eastern Indonesia is receiving special attention. BMKG urges high vigilance against the potential for rain accompanied by lightning or thunder in Manado and Ternate. Additionally, the Mamuju region is forecast to be hit by moderate-intensity rain.
Given the highly dynamic atmospheric conditions, BMKG urges the public to remain alert and continuously monitor weather updates through the official channel at bmkg.go.id or social media @infoBMKG.