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Grajaú fire, 25 August 2025 Grajaú

Out · last detection 10 Oct 2025, 03:39 UTC

The fire started on 25 August 2025 in Grajaú, Brazil, and satellites saw it burning for 47 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 61,698 hectares from heat detections, spread across a single municipality.

This page is probably a fire complex, not a single fire. GWIS merges into one perimeter the fires that touch over weeks, which in large burning seasons can join dozens of separate fires. The total area is reliable; the origin and dates refer to the whole complex.

Other fire pages in the same area and on the same dates:

It is the 3th largest in Maranhão since 2016 (of 607 with a page). Number 5 in Brazil in 2025, of 714.

Compare with…

Suggestions: Barra do Corda · 2017Grajaú · 2016Grajaú · 2016Grajaú · 2023

Burnt area
61,698ha
GWIS perimeter (Copernicus)
Duration
47days
25 Aug 2025 – 10 Oct 2025
Municipalities hit
1
municipalities
Started on
25 Aug
2025
Heat detections
1,970
in a single hotspot: 264 MW
Danger at start
40
Very high · FWI index
Average daily power
761MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 25 Aug10 Oct
10 Oct 2025

How it evolved, day by day

25 Aug 2025 · 22 MW · 3 26 Aug 2025 · 12 MW · 1 28 Aug 2025 · 7 MW · 1 1 Sept 2025 · 31 MW · 2 2 Sept 2025 · 29 MW · 2 3 Sept 2025 · 225 MW · 21 4 Sept 2025 · 842 MW · 30 5 Sept 2025 · 42 MW · 15 6 Sept 2025 · 209 MW · 26 7 Sept 2025 · 1,589 MW · 71 8 Sept 2025 · 2,192 MW · 76 9 Sept 2025 · 1,877 MW · 106 10 Sept 2025 · 1,646 MW · 160 11 Sept 2025 · 994 MW · 116 12 Sept 2025 · 110 MW · 21 13 Sept 2025 · 4 MW · 1 14 Sept 2025 · 26 MW · 3 15 Sept 2025 · 1,294 MW · 67 16 Sept 2025 · 1,314 MW · 182 17 Sept 2025 · 2,564 MW · 182 18 Sept 2025 · 2,640 MW · 166 19 Sept 2025 · 140 MW · 18 20 Sept 2025 · 15 MW · 2 21 Sept 2025 · 4 MW · 4 23 Sept 2025 · 36 MW · 7 24 Sept 2025 · 26 MW · 4 25 Sept 2025 · 4 MW · 1 27 Sept 2025 · 103 MW · 10 28 Sept 2025 · 906 MW · 63 29 Sept 2025 · 442 MW · 42 30 Sept 2025 · 2,676 MW · 95 1 Oct 2025 · 167 MW · 33 2 Oct 2025 · 551 MW · 63 3 Oct 2025 · 687 MW · 67 4 Oct 2025 · 3,856 MW · 136 5 Oct 2025 · 3,759 MW · 126 6 Oct 2025 · 24 MW · 8 7 Oct 2025 · 19 MW · 10 8 Oct 2025 · 65 MW · 20 9 Oct 2025 · 63 MW · 6 10 Oct 2025 · 7 MW · 3
25 Aug 4 Sept 10 Sept 16 Sept 23 Sept 30 Sept 4 Oct 6 Oct

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

The weather it burned in

38°high
44km/h · peak gust
20%lowest humidity

It had gone 12 days without rain (1 mm or more) when it started. Rain came after the fire: 2.0 mm on 11 Oct.

This area had burned before

88% of the perimeter overlaps earlier fires recorded since 2016: 31,235 ha in 2016, 42,868 ha in 2017, 2,488 ha in 2018, 7,052 ha in 2019, 32 ha in 2020, 8,594 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 54,273 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 39% of the area of London (617 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. Grajaú 73,872 inhabitants where it started
    62,114 ha reached on 25 Aug
    7.0 %

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 area6.2 ha
Residents≈ 1,800

Inside the perimeter there were about 6.2 hectares of built-up land and about 1,800 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)
25 Aug 35.7 °C 30 % 38 km/h 0.0 mm Very high 40
26 Aug 35.5 °C 28 % 36 km/h 0.0 mm Very high 39
27 Aug 35.5 °C 26 % 34 km/h 0.0 mm High 37
28 Aug 35.5 °C 24 % 31 km/h 0.0 mm Very high 39
29 Aug 35.2 °C 29 % 36 km/h 0.0 mm Very high 42
30 Aug 35.9 °C 28 % 40 km/h 0.2 mm Very high 43
31 Aug 35.4 °C 26 % 42 km/h 0.0 mm Very high 45
1 Sept 35.9 °C 28 % 42 km/h 0.0 mm Very high 46
2 Sept 36.0 °C 27 % 44 km/h 0.0 mm Very high 47
3 Sept 35.4 °C 28 % 42 km/h 0.0 mm Very high 47
4 Sept 35.6 °C 28 % 41 km/h 0.0 mm Very high 45
5 Sept 35.2 °C 28 % 43 km/h 0.0 mm Very high 48
6 Sept 35.9 °C 29 % 39 km/h 0.0 mm Very high 44
7 Sept 36.3 °C 28 % 36 km/h 0.0 mm Very high 43
8 Sept 36.4 °C 27 % 36 km/h 0.0 mm Very high 44
9 Sept 36.4 °C 26 % 37 km/h 0.0 mm Very high 44
10 Sept 37.2 °C 20 % 29 km/h 0.0 mm Very high 42
11 Sept 36.5 °C 35 % 31 km/h 0.0 mm Very high 38
12 Sept 33.4 °C 42 % 43 km/h 0.3 mm High 33
13 Sept 33.5 °C 43 % 35 km/h 0.6 mm High 29
14 Sept 34.9 °C 33 % 31 km/h 0.3 mm High 33
15 Sept 37.5 °C 23 % 34 km/h 0.0 mm Very high 42
16 Sept 36.6 °C 29 % 40 km/h 0.1 mm Very high 43
17 Sept 36.8 °C 30 % 40 km/h 0.0 mm Very high 45
18 Sept 36.1 °C 34 % 39 km/h 0.0 mm Very high 41
19 Sept 35.4 °C 36 % 32 km/h 0.1 mm High 37
20 Sept 33.7 °C 45 % 30 km/h 0.2 mm High 31
21 Sept 33.9 °C 43 % 33 km/h 0.1 mm High 32
22 Sept 33.2 °C 47 % 35 km/h 0.1 mm High 33
23 Sept 35.8 °C 40 % 37 km/h 0.1 mm High 30
24 Sept 35.6 °C 38 % 35 km/h 0.0 mm High 31
25 Sept 36.5 °C 29 % 32 km/h 0.0 mm High 36
26 Sept 34.8 °C 33 % 30 km/h 0.3 mm High 34
27 Sept 36.3 °C 26 % 38 km/h 0.0 mm Very high 42
28 Sept 36.3 °C 28 % 33 km/h 0.0 mm Very high 41
29 Sept 35.9 °C 33 % 36 km/h 0.0 mm Very high 41
30 Sept 37.2 °C 28 % 37 km/h 0.0 mm Very high 42
1 Oct 36.5 °C 29 % 35 km/h 0.0 mm Very high 43
2 Oct 35.9 °C 33 % 35 km/h 0.0 mm Very high 40
3 Oct 35.4 °C 30 % 34 km/h 0.1 mm Very high 40
4 Oct 35.8 °C 29 % 37 km/h 0.0 mm Very high 43
5 Oct 36.3 °C 26 % 44 km/h 0.0 mm Very high 46
6 Oct 36.7 °C 37 % 36 km/h 0.0 mm Very high 39
7 Oct 34.2 °C 45 % 32 km/h 0.1 mm High 30
8 Oct 35.8 °C 40 % 40 km/h 0.2 mm High 34
9 Oct 34.2 °C 43 % 29 km/h 0.2 mm High 33
10 Oct 34.8 °C 44 % 26 km/h 1.3 mm Moderate 19
11 Oct after 31.7 °C 54 % 27 km/h 2.0 mm Low 11

Before and after, from space

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

Before · 18 Aug 2025
After · 17 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 17 September 2025 the air beside the fire reached 39 µg/m³ of PM2.5. That day averaged 28: 1.8 times the WHO daily guideline (15).

PM2.5 peak39 µg/m³
Days over the guideline22 days
PM1040 µg/m³
Optical depth0.78
19202122232425262728293031123456789101112131415161718192021222324252627282930123456789101112131415161718
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 · 1,970Every 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 Brazil ›

Frequently asked questions

How long did the Grajaú fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 25 August 2025 to 10 October 2025 (47 days). The perimeter dates it from 31 August 2025 to 8 October 2025.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 61,698 hectares (617.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Grajaú (62,114 ha, 7.0 %).
What was the weather like?
During the fire the temperature reached 37.5 °C, humidity dropped to 20 % and gusts hit 44 km/h. The fire danger index (FWI) reached 48, class Very high.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Brazil (geoBoundaries). It is not an official report.

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: 193 · Emergency number and official warnings ›

Satellite cross-check

History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 8 October 2025 → 10 October 2025.
  2. Start date: 31 August 2025 → 25 August 2025.

RSS Changes to this page

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 193.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery; 6 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 31 August 2025 to 8 October 2025. 1,970 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.