How long did the Samoeng fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 21 March 2026 to 24 April 2026 (35 days). The perimeter dates it from 21 March 2026 to 20 April 2026.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 48,637 hectares (486.4 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 6 municipalities: Samoeng (24,686 ha, 24 %); Mae Wang (13,673 ha, 20 %); Hang Dong (4,651 ha, 18 %); Doi Lo (4,149 ha, 19 %); Chom Thong (1,141 ha, 1.0 %); Mae Rim (597 ha, 1.3 %).

What was the weather like?

During the fire the temperature reached 39.4 °C, humidity dropped to 21 % and gusts hit 37 km/h. The fire danger index (FWI) reached 39, class Very high.

Where does this data come from?

From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (geoBoundaries). It is not an official report.

TH · Thailand · 2026-03-21 → 2026-04-24

Samoeng fire, 21 March 2026 สะเมิง · Samoeng, Mae Wang, Hang Dong

Out · last detection 24 Apr 2026, 06:44 UTC

The fire started on 21 March 2026 in Samoeng, Thailand, and satellites saw it burning for 35 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 48,637 hectares from heat detections, spread across 6 municipalities.

It is the 2th largest in Chiang Mai Province since 2016 (of 399 with a page). Number 9 in Thailand in 2026, of 689.

Compare with…

Suggestions: Hang Dong · 2016 Samoeng · 2020 Samoeng · 2020 Doi Lo · 2024

Burnt area: 48,637ha; GWIS perimeter (Copernicus)
Duration: 35days; 21 Mar 2026 – 24 Apr 2026
Municipalities hit: 6; districts
Started on: 21 Mar; 2026
Heat detections: 1,117; in a single hotspot: 89 MW
Danger at start: 24; High · FWI index
Average daily power: 110MW; detected power per day, on average

HOTSPOTS BY DAY 21 Mar24 Apr

Play back 24 Apr 2026

How it evolved, day by day

21 Mar 26 Mar 29 Mar 31 Mar 5 Apr 10 Apr 15 Apr 22 Apr

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

The weather it burned in

39°high

37km/h · peak gust

21%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 2.5 mm on 25 Apr.

This area had burned before

95% of the perimeter overlaps earlier fires recorded since 2016: 21,884 ha in 2016, 10,052 ha in 2017, 6,542 ha in 2018, 22,667 ha in 2019, 25,644 ha in 2020, 9,906 ha in 2021, 3,584 ha in 2022, 20,764 ha in 2023, 23,490 ha in 2024, 1,084 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 46,148 ha that had burned before.

How big is it?

It burned the equivalent of 31% of the area of London (486 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

Samoeng สะเมิง where it started

24,686 ha reached on 21 Mar

24 %
Mae Wang แม่วาง

13,673 ha reached on 23 Mar

20 %
Hang Dong หางดง

4,651 ha reached on 21 Mar

18 %
Doi Lo ดอยหล่อ

4,149 ha reached on 24 Mar

19 %
Chom Thong จอมทอง

1,141 ha reached on 27 Mar

1.0 %
Mae Rim แม่ริม

597 ha reached on 29 Mar

1.3 %

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 area55 ha

Residents≈ 4,900

Inside the perimeter there were about 55 hectares of built-up land and about 4,900 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)
21 Mar	34.2 °C	38 %	31 km/h	0.3 mm	High 24
22 Mar	35.6 °C	29 %	35 km/h	0.0 mm	High 30
23 Mar	35.5 °C	28 %	27 km/h	0.0 mm	High 28
24 Mar	35.7 °C	26 %	28 km/h	0.0 mm	High 30
25 Mar	35.9 °C	24 %	29 km/h	0.0 mm	High 32
26 Mar	36.7 °C	24 %	23 km/h	0.0 mm	High 31
27 Mar	37.2 °C	23 %	32 km/h	0.0 mm	High 35
28 Mar	37.0 °C	25 %	36 km/h	0.1 mm	High 37
29 Mar	37.4 °C	21 %	37 km/h	0.0 mm	Very high 39
30 Mar	37.1 °C	27 %	31 km/h	0.0 mm	High 37
31 Mar	36.7 °C	31 %	24 km/h	0.0 mm	High 34
1 Apr	35.5 °C	36 %	23 km/h	0.0 mm	High 31
2 Apr	37.3 °C	30 %	27 km/h	0.0 mm	High 31
3 Apr	37.5 °C	30 %	27 km/h	0.0 mm	High 33
4 Apr	36.2 °C	36 %	24 km/h	0.0 mm	High 31
5 Apr	37.1 °C	35 %	24 km/h	0.0 mm	High 32
6 Apr	36.6 °C	36 %	24 km/h	0.0 mm	High 32
7 Apr	36.6 °C	35 %	30 km/h	0.0 mm	High 34
8 Apr	37.9 °C	24 %	31 km/h	0.0 mm	High 37
9 Apr	37.0 °C	28 %	29 km/h	0.0 mm	High 37
10 Apr	37.7 °C	25 %	35 km/h	0.0 mm	Very high 39
11 Apr	37.8 °C	24 %	31 km/h	0.0 mm	High 37
12 Apr	37.4 °C	28 %	25 km/h	0.0 mm	High 36
13 Apr	38.0 °C	30 %	26 km/h	0.0 mm	High 36
14 Apr	37.4 °C	32 %	26 km/h	0.0 mm	High 35
15 Apr	38.8 °C	24 %	30 km/h	0.0 mm	Very high 38
16 Apr	36.7 °C	31 %	24 km/h	0.0 mm	High 36
17 Apr	37.2 °C	29 %	20 km/h	0.0 mm	High 36
18 Apr	37.3 °C	34 %	23 km/h	0.0 mm	High 34
19 Apr	38.2 °C	27 %	30 km/h	0.0 mm	High 37
20 Apr	37.4 °C	32 %	28 km/h	0.0 mm	High 36
21 Apr	37.6 °C	37 %	23 km/h	0.0 mm	High 33
22 Apr	39.4 °C	30 %	25 km/h	0.0 mm	High 32
23 Apr	37.0 °C	40 %	28 km/h	0.9 mm	High 24
24 Apr	35.8 °C	43 %	28 km/h	0.1 mm	High 24
25 Apr after	30.6 °C	57 %	36 km/h	2.5 mm	Low 8

Before and after, from space

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

↔

Before · 14 Mar 2026

After · 1 May 2026

Before After

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 April 2026 the air beside the fire reached 150 µg/m³ of PM2.5. That day averaged 90: 6.0 times the WHO daily guideline (15).

PM2.5 peak150 µg/m³

Days over the guideline36 days

PM10160 µg/m³

Optical depth2.04

WHO 15

192021222324252627282930311234567891011121314151617181920212223

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 · 1,117Every 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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in Thailand ›

Frequently asked questions

How long did the Samoeng fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 21 March 2026 to 24 April 2026 (35 days). The perimeter dates it from 21 March 2026 to 20 April 2026.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 48,637 hectares (486.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 6 municipalities: Samoeng (24,686 ha, 24 %); Mae Wang (13,673 ha, 20 %); Hang Dong (4,651 ha, 18 %); Doi Lo (4,149 ha, 19 %); Chom Thong (1,141 ha, 1.0 %); Mae Rim (597 ha, 1.3 %).
What was the weather like?: During the fire the temperature reached 39.4 °C, humidity dropped to 21 % and gusts hit 37 km/h. The fire danger index (FWI) reached 39, class Very high.
Where does this data come from?: From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (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: 199 · 191 · Emergency number and official warnings ›

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

History of this page · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

26 October 2026 Last day with fire: 20 April 2026 → 24 April 2026.

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?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

What really happened?

Your connection to the fire (optional) Email (optional)

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 199 · 191.

How we know this

Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery; 7 polygons grouped in this page.
Dates adjusted with the VIIRS detections inside the perimeter, which said 21 March 2026 to 20 April 2026. 1,117 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.

Where it burned