BMKG Reveals El Niño Impact on Jakarta: Muggier Weather Forecast for September–October

The Meteorology, Climatology, and Geophysics Agency (BMKG) has predicted that the El Niño phenomenon will become active from mid-2026 until early 2027, detailing its impact on the Greater Jakarta area. “In general, the impact of El Niño on Jakarta is the same as in other regions of Java — we will experience a longer dry season,” said BMKG Deputy for Climatology Ardhasena Sopaheluwakan during a press conference on Wednesday. He noted that northern parts of Jakarta have already entered the dry season since May, while southern areas are expected to follow in June or July. Consequently, the main effect of El Niño in Jakarta will be a prolonged dry season. In terms of temperature, the BMKG forecasts hotter, muggier conditions, particularly because the sun is predicted to be directly overhead above Java in September and October. “Regarding temperature, Jakarta usually feels more ‘sumuk’ — as the Javanese say — around late September to October, precisely when the sun passes over the island of Java,” he added. The BMKG expects the peak of the dry season to occur between July and September 2026, resulting in dry air due to minimal rainfall. “Around July and August, the dry air arising from scarce rainfall will be accompanied by low humidity. This is a typical characteristic of Java during the peak dry season, with temperatures then rising around September and October,” he stated. Regarding air quality, the BMKG explained that reduced rainfall does not necessarily increase pollutant levels but rather means pollutants are not washed away. “The lack of rain does not mean air quality worsens or pollutants increase, but rather that pollutants are not cleansed from the atmosphere. Sources of pollutants exist constantly through human activities such as transport, factories and power plants. The absence of rain hinders the improvement of air quality because there is no atmospheric washing by precipitation,” he said. Earlier, BMKG Chief Teuku Faisal Fathani confirmed during the same press conference that the El Niño phenomenon is expected to become active from mid-2026, with a 98 per cent probability of moderate intensity and a 62 per cent probability of strong intensity. The BMKG has urged the government and relevant stakeholders to immediately prepare anticipatory measures and mitigation efforts to address the potential suppression of rainfall.