Indonesia: El Nino's impact to decrease by mid-October 2026, says BMKG

Indonesia's national weather agency, BMKG, forecasts that the effects of El Nino will begin to subside by mid-October 2026 as the rainy season commences across most of the archipelago. While El Nino is expected to persist until around May 2027, its influence on national weather patterns is predicted to diminish significantly compared to the dry season.

BMKG Head Teuku Faisal Fathani emphasized the distinction between El Nino and the dry season. He explained that the dry season is a natural, recurring cycle, whereas El Nino is a climate anomaly that intensifies drought conditions when it coincides with the dry season, leading to reduced rainfall and prolonged dry spells.

Faisal noted that BMKG had anticipated a moderate El Nino coinciding with the dry season since March 2026, with its intensity increasing over time. The World Meteorological Organization confirmed El Nino's active status on June 2, 2026, and monitoring data from May to July indicated it had entered a strong phase. However, Fathani clarified that a strong phase does not mean uniform impacts across Indonesia due to the nation's diverse geography as an archipelago.

BMKG utilizes a detailed system of 699 distinct "season zones" across Indonesia to precisely map the localized impacts of El Nino and tailor mitigation strategies. Regions south of the equator, including East Nusa Tenggara, West Nusa Tenggara, Bali, much of Java's coastal areas, southern Sumatra, and southern Papua, are projected to experience the most significant effects. Conversely, areas west of the Barisan Mountains, the northern belt of Kalimantan, parts of Papua, and Maluku may see different climatic characteristics, leading to varied El Nino impacts.

Faisal also cautioned against comparing current El Nino events to past occurrences like those in 2015, 2019, or 2023, as each El Nino has unique characteristics. He stated that even a very strong El Nino, such as the one in 2015, has its impact on Indonesia moderated by atmospheric dynamics and sea surface temperatures around the archipelago. Warmer sea surface temperatures, for instance, can still foster cloud formation and mitigate drought effects in certain areas.

“

When the rainy season begins, expected around the third week of October, El Nino will no longer significantly affect Indonesia, even though it remains active until around May 2027.