At the beginning of September 2025, Indonesia is experiencing severe weather conditions, particularly in the form of heavy rains and flash floods, which have caused significant disruption and loss of life. The archipelago nation, prone to tropical downpours, is transitioning toward its wet season, with recent events highlighting the intensity of these conditions. This report summarises the latest developments, with a focus on the impacts in key areas, including Bali and East Nusa Tenggara.
Recent Flash Floods in Bali
Bali, Indonesia’s premier tourist destination, has been hit hardest by the bad weather. Continuous heavy rains from September 9 to September 10, 2025, triggered flash floods across multiple districts, marking the island’s worst flooding in a decade. At least 14 people have been confirmed dead, with reports varying slightly across sources. Initial figures cited nine fatalities, but updated counts from officials and media outlets confirm the higher toll. The floods affected over 600 people, leading to evacuations and the collapse of two buildings in the capital, Denpasar.
Key impacts include:
– Deaths and Injuries: Four deaths in Denpasar due to building collapses, one in Badung County, and two in the Jembrana district. An additional 85 residents were evacuated to temporary shelters in Jembrana.
– Infrastructure Damage: Major roads in Denpasar and surrounding areas were blocked, limiting access to Bali’s international airport near Denpasar—only trucks could navigate the flooded routes. Popular tourist spots in Legian and Badung were inundated, forcing hotels and businesses to halt operations.
– Contributing Factors: Officials attribute the severity to clogged drainage systems exacerbated by rubbish accumulation, a longstanding waste management issue in Bali. Climate change has intensified these events, making landslides and floods more frequent and severe.
President Prabowo Subianto has expressed condolences and deployed the head of the national disaster agency to Bali to oversee emergency responses, ensuring that basic needs such as food and shelter are met. A severe weather warning remains in effect, though rains are expected to ease slightly from September 11 onward.
Floods in East Nusa Tenggara
The bad weather has also struck East Nusa Tenggara province, including areas near Labuan Bajo and Komodo National Park. In Nagekeo district, four people died, and four remain missing due to flash floods from the same heavy rainfall system. This region, popular for diving and eco-tourism, saw widespread inundation, disrupting local communities and travel. The floods here are part of a broader pattern affecting Indonesia’s eastern islands, where mountainous terrain amplifies runoff.
Broader Weather Context in September 2025
September typically marks the end of Indonesia’s dry season and the onset of wetter conditions, especially in western and central regions. Average temperatures range from 27 to 31°C (81 to 88°F), with humidity making the heat feel oppressive. While historical data shows only about 4–6 rainy days on average, 2025 has seen an unusually intense start to the transition. Coastal areas, such as Bali, experience occasional showers, but central and eastern parts, including Sumatra and Borneo, face more frequent downpours. By late September, the wet season has a significant impact on western Indonesia, increasing the risk of similar events in the future.
As of September 12, there have been no widespread reports of bad weather in other significant areas, such as Java or Sumatra. However, the national meteorological agency has issued a warning of potential landslides and further flooding nationwide. Travelers should monitor updates from the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG).
Advice for Travelers and Residents
With bad weather disrupting flights, ferries, and roads, those planning trips to affected areas should consider postponing or rerouting their travel plans. Airlines like Garuda Indonesia have issued advisories for Bali. Residents in flood-prone areas are advised to stay away from low-lying areas and clear drains to minimise risks. For real-time updates, check official sources, such as BMKG or local disaster agencies.
Indonesia’s vulnerability to extreme weather highlights the need for enhanced infrastructure and improved climate resilience. As the nation grapples with these events, international support and local efforts are crucial for recovery.
