Skip to content
worldfires
ID · Indonesia · –

Sekadau fire, 19 September 2025 Sekadau

Out · last detection 27 Sept 2025, 06:53 UTC

The fire started on 19 September 2025 in Sekadau, Indonesia, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 20,686 hectares from heat detections, spread across a single municipality.

It is the largest fire in West Kalimantan since 2016 (of 129 with a page). The largest in Indonesia in 2025, of 43.

Burnt area
20,686ha
GWIS perimeter (Copernicus)
Duration
9days
19 Sept 2025 – 27 Sept 2025
Municipalities hit
1
regencies
Started on
19 Sept
2025
Heat detections
371
in a single hotspot: 149 MW
Danger at start
0
Very low · FWI index
Average daily power
742MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 19 Sept27 Sept
27 Sept 2025

How it evolved, day by day

19 Sept 2025 · 15 MW · 2 22 Sept 2025 · 1,571 MW · 105 23 Sept 2025 · 2,043 MW · 146 24 Sept 2025 · 1,240 MW · 92 25 Sept 2025 · 94 MW · 8 26 Sept 2025 · 89 MW · 6 27 Sept 2025 · 141 MW · 12
19 Sept 23 Sept 25 Sept 27 Sept

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

36°high
22km/h · peak gust
45%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 6.2 mm on 28 Sept.

This area had burned before

24% of the perimeter overlaps earlier fires recorded since 2016: 1,292 ha in 2016, 238 ha in 2017, 122 ha in 2018, 126 ha in 2019, 228 ha in 2020, 1,688 ha in 2021, 621 ha in 2023, 1,209 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 4,894 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 13% of the area of London (207 km² against 1,583 km²).

London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).

This compares size, not location: both shapes are at the same scale, north up, centred on each other.

What happened to each town

  1. Sekadau where it started
    20,826 ha reached on 19 Sept
    3.6 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance runs from the point marking the centre of each area to the nearest fire: staying a kilometre away does not mean it reached the houses.

People and buildings inside the perimeter

GHSL 2025
Built-up area21 ha
Residents≈ 5,300

Inside the perimeter there were about 21 hectares of built-up land and about 5,300 residents (GHSL 2025, satellite-based estimate).

This is an estimate on 100 m cells, made from satellite imagery and census data: it does not mean that homes burned or that anyone was harmed. The perimeter also contains land that never burned. The GHSL 2025 epoch is a projection made from 2020 and earlier data.

Source: Global Human Settlement Layer (GHS-BUILT-S and GHS-POP R2023A), European Commission Joint Research Centre (JRC), © European Union, CC BY 4.0. Sum inside the perimeter computed by WorldFires. human-settlement.emergency.copernicus.eu

The weather day by day

ECMWF ERA5 reanalysis at the fire location, the standard reference for past weather, and the Canadian Fire Weather Index (the same system Copernicus uses), computed by WorldFires from that data. Days after the fire run until the first rain.

Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

Day High Min. humidity Peak gust Rain Danger (FWI)
19 Sept 33.3 °C 58 % 20 km/h 5.7 mm Very low 0
20 Sept 31.7 °C 63 % 17 km/h 7.4 mm Very low 0
21 Sept 31.3 °C 68 % 17 km/h 6.7 mm Very low 0
22 Sept 34.6 °C 55 % 22 km/h 0.1 mm Very low 0
23 Sept 33.9 °C 54 % 17 km/h 0.5 mm Very low 2
24 Sept 35.0 °C 51 % 16 km/h 0.8 mm Very low 3
25 Sept 33.7 °C 56 % 18 km/h 0.4 mm Very low 4
26 Sept 34.6 °C 48 % 18 km/h 0.0 mm Very low 5
27 Sept 35.6 °C 45 % 16 km/h 0.2 mm Low 7
28 Sept after 35.2 °C 56 % 18 km/h 6.2 mm Very low 0

Its twins: fires that started in the same weather

It started with an FWI of 0.2, a minimum humidity of 58% and rain the day before. Fires in the area that started in weather like this since 2016: 31.

FWI at the start 0.2
Minimum humidity 58 %
Days without rain 0
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Sintang fire, July 2023
1,921 ha 7 days FWI 0.8 Min. humidity 58 % 104 km away, in 2023

First rain (1 mm or more) after it ended: 3.8 mm on 2 Aug.

What happened to them

5 days
median duration
1,921 ha
median area
77 %
went past 1,000 ha
5.2 mm
rain at the end (median; 31 of 31 had it)

It was 10.8 times larger than the median of its twins and lasted 9 days, against 5 days.

None of its 31 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 5.2 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

6.2 mmfirst rain
28 Septthe day after it ended
22km/h · max. gust

It was considered over on 27 Sept, and on 28 Sept 6.2 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 31 of 31, with a median of 5.2 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 12 Sept 2025
After · 4 Oct 2025

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

The smoke

CAMS · Copernicus

On 25 September 2025 the air beside the fire reached 352 µg/m³ of PM2.5. That day averaged 181: 12 times the WHO daily guideline (15).

PM2.5 peak352 µg/m³
Days over the guideline10 days
PM10358 µg/m³
Optical depth2.44
13 Sept17 Sept21 Sept25 Sept29 Sept
Good Fair Moderate Poor Very poor Extremely poor

Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.

Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)

Detections table · 371Every satellite heat detection, one by one, with time, satellite, power and coordinates.
⬇ Download CSV Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Date and timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in Indonesia

Frequently asked questions

How long did the Sekadau fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 19 September 2025 to 27 September 2025 (9 days). The perimeter dates it from 21 September 2025 to 27 September 2025.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 20,686 hectares (206.9 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Sekadau (20,826 ha, 3.6 %).
What was the weather like?
During the fire the temperature reached 35.6 °C, humidity dropped to 45 % and gusts hit 22 km/h. The fire danger index (FWI) reached 7, class Low.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Indonesia (geoBoundaries). It is not an official report.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 31. Their median duration was 5 days and their median area 1,921 ha; 77 % went past 1,000 ha. None of its 31 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 5.2 mm.

Where to verify it

A satellite detection is not an official report. Final figures and the fire’s status are published by each country’s emergency service.

Emergency number: 112 · Emergency number and official warnings

Satellite cross-check

History of this page · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Start date: 21 September 2025 → 19 September 2025.

RSS Changes to this page With cross-checks and a citable version

Does something look wrong on this page?

This page is built from satellite data and official records, and it sometimes gets things wrong: the wrong dates, the wrong town, two fires merged into one, or something that was not a wildfire at all. If you know this fire first-hand (you live nearby, saw it, fought it or reported on it), tell us what really happened and we will check it.

Report an error
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 112.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery; 2 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 21 September 2025 to 27 September 2025. 371 Suomi-NPP VIIRS detections on those dates.
  • We have not matched this page with any official record.
  • Weather: Copernicus ERA5 reanalysis at the fire location, in cells of about 25 km.
  • Built-up area and population come from the JRC Global Human Settlement Layer (epoch 2025, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.

How we build fire pages: methodology

Where this data comes from

The perimeter comes from the Copernicus Global Wildfire Information System (GWIS), which rebuilds it from MODIS and VIIRS heat detections and publishes it under CC BY 4.0. It is not measured on imagery as in Europe, so it is an estimate. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. Municipal boundaries come from geoBoundaries ADM2 (Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ from each country’s official figure.