Indonesia Braces for October 2026 Rains: BMKG Forecasts

The Meteorology, Climatology, and Geophysics Agency (BMKG) of Indonesia estimates that the peak of the dry season in some parts of the country will continue until the end of October. Following this, the rainy season is expected to return around October 2026. Ardhasena Sopaheluwakan, Deputy for Climatology at BMKG, announced that the dry season in 2026 is projected to end around mid-October. "Generally, the dry season of 2026 in Indonesia will end around mid-October," Ardhasena said during an online press conference in Jakarta late last July. The rainy season will gradually spread to various regions after they emerge from the dry season, he said. According to him, the rainy season is expected to arrive earlier in the western parts of Indonesia. Furthermore, the rainy season is predicted to begin to spread widely and wet several other regions in Indonesia in November. These regions include most of Java Island. According to Ardhasena, this condition is indicated by climate forecast maps showing yellow colors in October and November. This color signifies that the rainy season will begin to arrive. "In October and November, we start to see yellow colors indicating that rain in Indonesia is starting to normalize, although we also see that in November, rain in Java, for example, is still below normal, but the rain has started to come and enter the Java region," he explained. Ardhasena explained that the 2026 rainy season will occur concurrently with the El Niño phenomenon. This is because the phenomenon, which triggers drier conditions, is predicted to last until early 2027 and will only reach its peak in December 2026. Despite this, he stated that El Niño will not significantly affect the rainy season. The impact of this phenomenon is said to be most felt when entering the peak of the dry season. "The impact of El Niño in Indonesia also greatly depends on the condition of the hot sea around the Indonesian region. So, its impact will not necessarily be exactly the same as in previous years," he said. "There is no single El Niño event that is always the same as the previous year's El Niño, nor is there always the same impact with subsequent El Niño events," he added. Meanwhile, the peak of the dry season is still expected to continue until the end of October in some parts of Indonesia. According to BMKG, the duration of this year's dry season ranges from three to seven months, depending on the region. The dry season has the potential to be longer in 437 Musim Zone (ZOM), which covers 48.77 percent of Indonesia's land area. "The peak of the dry season is still expected to continue until the end of October 2026," said Head of BMKG Teuku Faisal Fathani in a statement on BMKG's official website, Thursday (17/8). According to Faisal, efforts for prevention, preparedness, and mitigation need to be continuously strengthened until the rainy season period begins. Moreover, some areas are currently still experiencing forest and land fires. This dry season condition, he said, is also influenced by a very strong El Niño phenomenon, which has the potential to increase the risk of forest and land fires for the next few weeks. According to BMKG, in the period from the third 10-day period of September to the second 10-day period of October 2026, rainfall in most parts of Indonesia is predicted to still be in the low to moderate category, around 0-150 mm per 10-day period. This condition indicates that the supply of water vapor to support the formation of rain clouds is still relatively limited, one of which is related to the influence of a very strong El Niño which tends to reduce moisture supply to the Indonesian region, so dry conditions are still likely to continue in several regions. Source: CNN Indonesia