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Mueang Mae Hong Son fire, 17 March 2026 เมืองแม่ฮ่องสอน · Mueang Mae Hong Son, Khun Yuam, Pai

Out · last detection 24 Apr 2026, 19:15 UTC

The fire started on 17 March 2026 in Mueang Mae Hong Son, Thailand, and satellites saw it burning for 39 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 130,783 hectares from heat detections, spread across 4 municipalities.

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:

Number 2 in Thailand in 2026, of 688.

GWIS near-real-time perimeter, from the layer that changed in October 2025: this fire is not compared with fires from earlier years, because since then the GWIS layer gives more and larger perimeters.

Compare with…

Suggestions: Mueang Mae Hong Son · 2025Mueang Mae Hong Son · 2025Pang Mapha · 2024Mueang Mae Hong Son · 2017

Burnt area
130,783ha
GWIS perimeter (Copernicus)
Duration
39days
17 Mar 2026 – 24 Apr 2026
Municipalities hit
4
districts
Started on
17 Mar
2026
Heat detections
4,654
in a single hotspot: 76 MW
Danger at start
13
Moderate · FWI index
Average daily power
431MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 17 Mar24 Apr
24 Apr 2026

How it evolved, day by day

17 Mar 2026 · 11 MW · 2 18 Mar 2026 · 4 MW · 4 19 Mar 2026 · 4 MW · 3 21 Mar 2026 · 5 MW · 5 22 Mar 2026 · 39 MW · 13 23 Mar 2026 · 300 MW · 62 24 Mar 2026 · 136 MW · 44 25 Mar 2026 · 82 MW · 33 26 Mar 2026 · 330 MW · 79 27 Mar 2026 · 680 MW · 161 28 Mar 2026 · 1,398 MW · 384 29 Mar 2026 · 1,364 MW · 430 30 Mar 2026 · 596 MW · 178 31 Mar 2026 · 283 MW · 56 1 Apr 2026 · 459 MW · 123 2 Apr 2026 · 1,273 MW · 383 3 Apr 2026 · 1,343 MW · 402 4 Apr 2026 · 293 MW · 83 5 Apr 2026 · 222 MW · 63 6 Apr 2026 · 247 MW · 56 7 Apr 2026 · 778 MW · 165 8 Apr 2026 · 1,092 MW · 420 9 Apr 2026 · 946 MW · 307 10 Apr 2026 · 365 MW · 137 11 Apr 2026 · 623 MW · 151 12 Apr 2026 · 689 MW · 180 13 Apr 2026 · 825 MW · 263 14 Apr 2026 · 371 MW · 133 15 Apr 2026 · 189 MW · 51 16 Apr 2026 · 180 MW · 36 17 Apr 2026 · 110 MW · 21 18 Apr 2026 · 316 MW · 64 19 Apr 2026 · 176 MW · 40 20 Apr 2026 · 47 MW · 16 21 Apr 2026 · 20 MW · 10 22 Apr 2026 · 490 MW · 73 23 Apr 2026 · 35 MW · 8 24 Apr 2026 · 48 MW · 15
17 Mar 28 Mar 3 Apr 11 Apr 19 Apr

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

Fire front film How it spread from one satellite pass to the next (81 passes) and with what wind. Watch the film

The weather it burned in

38°high
46km/h · peak gust
25%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 9.2 mm on 25 Apr.

This area had burned before

97% of the perimeter overlaps earlier fires recorded since 2016: 49,987 ha in 2016, 43,760 ha in 2017, 34,667 ha in 2018, 68,029 ha in 2019, 60,000 ha in 2020, 61,199 ha in 2021, 31,119 ha in 2022, 44,105 ha in 2023, 57,779 ha in 2024, 49,809 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 126,814 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 83% of the area of London (1,308 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. Mueang Mae Hong Son เมืองแม่ฮ่องสอน where it started
    84,613 ha reached on 17 Mar
    36 %
  2. Khun Yuam ขุนยวม
    23,269 ha reached on 24 Mar
    14 %
  3. Pai ปาย
    20,530 ha reached on 24 Mar
    8.9 %
  4. Pang Mapha ปางมะผ้า
    4,537 ha reached on 23 Mar
    4.1 %

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 area90 ha
Residents≈ 6,500

Inside the perimeter there were about 90 hectares of built-up land and about 6,500 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)
17 Mar 31.5 °C 44 % 31 km/h 0.1 mm Moderate 13
18 Mar 33.9 °C 35 % 29 km/h 0.0 mm Moderate 17
19 Mar 34.1 °C 34 % 32 km/h 0.0 mm Moderate 19
20 Mar 32.6 °C 40 % 30 km/h 0.0 mm Moderate 20
21 Mar 34.9 °C 37 % 36 km/h 0.2 mm High 22
22 Mar 34.4 °C 35 % 45 km/h 0.2 mm High 24
23 Mar 34.1 °C 34 % 39 km/h 0.0 mm High 23
24 Mar 35.0 °C 27 % 37 km/h 0.0 mm High 26
25 Mar 34.9 °C 28 % 38 km/h 0.0 mm High 27
26 Mar 35.8 °C 26 % 35 km/h 0.0 mm High 28
27 Mar 36.0 °C 29 % 40 km/h 0.0 mm High 30
28 Mar 36.5 °C 27 % 46 km/h 0.0 mm High 32
29 Mar 36.5 °C 25 % 46 km/h 0.0 mm High 34
30 Mar 36.2 °C 31 % 40 km/h 0.0 mm High 33
31 Mar 36.6 °C 34 % 37 km/h 0.0 mm High 31
1 Apr 36.6 °C 34 % 35 km/h 0.0 mm High 32
2 Apr 37.2 °C 31 % 37 km/h 0.0 mm High 33
3 Apr 37.6 °C 30 % 35 km/h 0.0 mm High 33
4 Apr 36.2 °C 37 % 32 km/h 0.0 mm High 31
5 Apr 36.2 °C 41 % 36 km/h 0.0 mm High 30
6 Apr 35.6 °C 42 % 34 km/h 0.0 mm High 29
7 Apr 34.4 °C 46 % 40 km/h 0.4 mm High 28
8 Apr 36.6 °C 31 % 43 km/h 0.0 mm High 33
9 Apr 35.2 °C 37 % 40 km/h 0.0 mm High 33
10 Apr 35.4 °C 34 % 41 km/h 0.0 mm High 33
11 Apr 36.0 °C 32 % 42 km/h 0.0 mm High 33
12 Apr 36.5 °C 31 % 35 km/h 0.0 mm High 32
13 Apr 37.1 °C 34 % 37 km/h 0.2 mm High 33
14 Apr 37.4 °C 33 % 35 km/h 0.0 mm High 33
15 Apr 37.3 °C 33 % 38 km/h 0.0 mm High 34
16 Apr 36.2 °C 36 % 32 km/h 0.1 mm High 32
17 Apr 37.2 °C 33 % 27 km/h 0.0 mm High 33
18 Apr 36.7 °C 39 % 32 km/h 0.2 mm High 33
19 Apr 36.0 °C 38 % 43 km/h 0.8 mm High 29
20 Apr 35.4 °C 40 % 39 km/h 0.1 mm High 29
21 Apr 36.3 °C 41 % 35 km/h 0.2 mm High 28
22 Apr 37.6 °C 37 % 35 km/h 0.1 mm High 30
23 Apr 36.7 °C 40 % 37 km/h 0.2 mm High 32
24 Apr 37.6 °C 39 % 28 km/h 0.0 mm High 29
25 Apr after 32.8 °C 55 % 29 km/h 9.2 mm Very low 4

Before and after, from space

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

Before · 10 Mar 2026
After · 1 May 2026

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 3 April 2026 the air beside the fire reached 115 µg/m³ of PM2.5. That day averaged 71: 4.8 times the WHO daily guideline (15).

PM2.5 peak115 µg/m³
Days over the guideline38 days
PM10128 µg/m³
Optical depth1.52
17 Mar26 Mar4 Apr13 Apr22 Apr
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 · 4,654Every 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 Thailand

Frequently asked questions

How long did the Mueang Mae Hong Son fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 17 March 2026 to 24 April 2026 (39 days). The perimeter dates it from 19 March 2026 to 24 April 2026.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 130,783 hectares (1,307.8 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 4 municipalities: Mueang Mae Hong Son (84,613 ha, 36 %); Khun Yuam (23,269 ha, 14 %); Pai (20,530 ha, 8.9 %); Pang Mapha (4,537 ha, 4.1 %).
What was the weather like?
During the fire the temperature reached 37.6 °C, humidity dropped to 25 % and gusts hit 46 km/h. The fire danger index (FWI) reached 34, class 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

History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Area: 133,850 → 130,783 ha.
  2. Start date: 19 March 2026 → 17 March 2026.

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 199 · 191.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery; 13 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 19 March 2026 to 24 April 2026. 4,654 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.