Weather conditions across parts of Indonesia remain unstable as BMKG has issued an early warning for July 15-17, 2026. Several regions are at risk of moderate to heavy rain, while others are on alert for strong winds.
No area is forecast to face heavy to very heavy rain today, and BMKG has not placed any region in the highest alert category for extreme rainfall. Even so, the agency said the combination of seasonal and atmospheric factors still warrants caution.
Areas with a risk of moderate to heavy rain
| Region | Status | Expected Condition |
|---|---|---|
| North Sumatra | Alert | Moderate to heavy rain |
| Riau Islands | Alert | Moderate to heavy rain |
| West Kalimantan | Alert | Moderate to heavy rain |
| North Kalimantan | Alert | Moderate to heavy rain |
| Central Sulawesi | Alert | Moderate to heavy rain |
| West Sulawesi | Alert | Moderate to heavy rain |
| South Sulawesi | Alert | Moderate to heavy rain |
Areas on alert for strong winds
| Region | Status | Expected Condition |
|---|---|---|
| Banten | High Alert | Strong winds |
| East Java | High Alert | Strong winds |
| South Kalimantan | High Alert | Strong winds |
| Lampung | High Alert | Strong winds |
| Maluku | High Alert | Strong winds |
| West Nusa Tenggara | High Alert | Strong winds |
| East Nusa Tenggara | High Alert | Strong winds |
| West Papua | High Alert | Strong winds |
| South Sulawesi | High Alert | Strong winds |
| Southeast Sulawesi | High Alert | Strong winds |
| North Sulawesi | High Alert | Strong winds |
The broader outlook suggests the dry season is becoming more dominant and is nearing its peak in many regions. BMKG said 432 climate zones, or about 60.5 percent of Indonesia, were already in the dry season during the first ten-day period of July 2026.
For the second ten-day period of July 2026, around 91.45 percent of Indonesia is expected to record low rainfall. Another 8.52 percent is forecast to receive moderate rainfall, while only about 0.03 percent is projected to see high rainfall.
Low rainfall, defined as less than 50 mm per ten-day period, is expected in most of Sumatra, Java, Bali, West Nusa Tenggara, East Nusa Tenggara, Kalimantan, and Sulawesi. Similar conditions are also expected in North Maluku, Maluku, and parts of Papua.
Despite the expanding dry season, atmospheric disturbances can still support cloud growth and localized rain. The Kelvin wave is forecast to be active across parts of Aceh, North Sumatra, West Sumatra, Riau, northern Sulawesi, and North Maluku.
At the same time, the equatorial Rossby wave is expected to influence East Nusa Tenggara, West Nusa Tenggara, Bali, Java, central to southern Sumatra, and central to southern Sulawesi. Together, these factors explain why rain and strong winds remain a concern in a number of areas.