BMKG Predicts Rainy Season to Arrive in November
The Meteorology, Climatology, and Geophysics Agency (BMKG) has predicted that the rainy season will begin to spread across Indonesia in November 2026. Meanwhile, August through September is expected to remain the peak of the dry season in most regions.
BMKG’s Deputy for Climatology, Ardhasena Sopaheluwakan, explained that this is evident from the climate forecast map, which shows a dominance of brown to dark brown colours in August and September, indicating dry conditions.
“We can also see that in the coastal areas of Riau, North Sumatra, and Aceh, the colours are yellow and even green, which shows what we mentioned earlier — that these areas have a different climate type. For October, we see yellowish colours starting to appear more widely compared to September,” Ardhasena said at a press conference at his office on Thursday (30/7/2026).
He explained that the appearance of yellow on the map is an early indicator that the rainy season is beginning to enter western Indonesia. Moving into November, the yellow areas are expected to expand further.
“So in November, as we can see in the bottom right of the map, the majority is already yellowish — the rainy season is beginning,” he said.
Meanwhile, El Niño is predicted to persist until early 2027. Ardhasena also emphasised that El Niño is not the same as the dry season.
“The dry season is not the same as El Niño. El Niño will continue until early 2027, but its impact on us will end from mid-October, continuing into November,” he said.
In addition, BMKG presented its monthly rainfall characteristics forecast. In August and September, most of Indonesia is predicted to still experience below-normal rainfall. From October to November, rainfall conditions are expected to gradually return to normal in many areas.
“In October and November, yellow colours begin to appear, showing that rainfall in Indonesia is returning to normal. Although in November, for example, rainfall on Java Island is still below normal, the rains have begun to arrive and enter Java Island,” he said.