Burned area
satellite only32,058ha
Union of 6 GWIS (Copernicus) perimeters: overlapping areas count once.
- Source
- GWIS (Copernicus)
- Date
- 4 Mar 2025 – 10 Apr 2025
+− cross-check
No official record is matched to this page to compare it with.
TH · Thailand · –
Mueang Mae Hong Son fire, 4 March 2025 เมืองแม่ฮ่องสอน · Mueang Mae Hong Son, Khun Yuam
Out · last detection 11 Apr 2025, 06:24 UTC
The fire started on 4 March 2025 in Mueang Mae Hong Son, Thailand, and satellites saw it burning for 38 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 32,058 hectares from heat detections, spread across 2 municipalities.
It is the 2th largest in Mae Hong Son Province since 2016 (of 361 with a page). The largest in Thailand in 2025, of 173.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-26matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only38days
4 Mar 2025 to 10 Apr 2025: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 11 Apr 2025, 06:24 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only4 Mar 2025
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 4 Mar 2025
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only1,330
VIIRS detections at 375 m. Most intense hotspot: 51 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 4 Mar 2025 – 10 Apr 2025
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only473MW
Total radiative power on 31 March 2025; hotspots that day: 138.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 31 Mar 2025
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model19.9FWI · moderate
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 6.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 4 Mar 2025, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model37.7°C · 21% RH
High of 37.7 °C and minimum humidity of 21% on 30 March 2025; gusts of 46 km/h on 5 April 2025.
- Source
- weather model at the fire’s grid cell
- Date
- 4 Mar 2025 – 10 Apr 2025
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
Living inside
model≈ 1,200people
Estimated residents inside the perimeter and 16 ha of built-up area (100 m grid, epoch 2025).
- Source
- GHSL R2023A · JRC
- Date
- calculated on 24 October 2026
+− cross-check
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.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
logLast day with fire: 4 April 2025 → 10 April 2025.
-
logStart date: 7 March 2025 → 4 March 2025.
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 26 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 32,440 ha
- Dates
- 4 Mar 2025 – 10 Apr 2025
- Name
- Mueang Mae Hong Son
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/mueang-mae-hong-son-2025-03?v=2026-10-26A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire mueang-mae-hong-son-2025-03.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025-03-04 | 6 | 9 | 31.7 | 16.5 | 32 | 10.5 | 32.4 | 0 | 19.9 | moderado | 1 |
| 2025-03-05 | 6 | 11 | 31.4 | 16.7 | 35 | 10.9 | 33.1 | 0 | 20.7 | moderado | 1 |
| 2025-03-06 | 0 | 0 | 32.1 | 15.1 | 31 | 11.1 | 32 | 0 | 21.6 | alto | 1 |
| 2025-03-07 | 4 | 14 | 34.7 | 14.1 | 26 | 16.1 | 45.7 | 0 | 28.6 | alto | 1 |
| 2025-03-08 | 2 | 9 | 31.1 | 19.3 | 44 | 13.4 | 40 | 0 | 22.5 | alto | 1 |
| 2025-03-09 | 9 | 11 | 31.8 | 19.3 | 40 | 9.8 | 30.2 | 0 | 20.9 | moderado | 1 |
| 2025-03-10 | 12 | 36 | 32.6 | 18.3 | 41 | 9 | 22 | 0.2 | 21 | moderado | 1 |
| 2025-03-11 | 7 | 41 | 33.5 | 19.6 | 37 | 11.9 | 35.3 | 0 | 23.2 | alto | 1 |
| 2025-03-12 | 2 | 20 | 31.6 | 19.2 | 44 | 12.9 | 38.5 | 0.5 | 23.3 | alto | 1 |
| 2025-03-13 | 15 | 55 | 34.4 | 19.6 | 30 | 12.8 | 39.6 | 0 | 26.8 | alto | 1 |
| 2025-03-14 | 22 | 134 | 34.2 | 19.1 | 29 | 10.7 | 30.6 | 0 | 26.5 | alto | 1 |
| 2025-03-15 | 30 | 62 | 35.1 | 18.2 | 28 | 9.9 | 31 | 0 | 27.3 | alto | 1 |
| 2025-03-16 | 13 | 60 | 34.8 | 19.6 | 30 | 12 | 33.5 | 0 | 29.3 | alto | 1 |
| 2025-03-17 | 11 | 38 | 35.5 | 20.4 | 29 | 12.2 | 36.7 | 0 | 30.1 | alto | 1 |
| 2025-03-18 | 24 | 67 | 34.4 | 21.3 | 35 | 12.5 | 36.7 | 0 | 30.8 | alto | 1 |
| 2025-03-19 | 79 | 210 | 31.2 | 21.6 | 45 | 9.8 | 28.4 | 0.4 | 24 | alto | 1 |
| 2025-03-20 | 126 | 323 | 31.7 | 19.2 | 39 | 9.2 | 27.4 | 0 | 24 | alto | 1 |
| 2025-03-21 | 69 | 159 | 31.2 | 20 | 41 | 8.5 | 20.5 | 0 | 23.9 | alto | 1 |
| 2025-03-22 | 55 | 70 | 33.1 | 19.4 | 39 | 9.6 | 23.4 | 0 | 24.9 | alto | 1 |
| 2025-03-23 | 24 | 59 | 33.6 | 19.9 | 40 | 9.4 | 28.1 | 0 | 25.1 | alto | 1 |
| 2025-03-24 | 28 | 77 | 34.4 | 19.5 | 32 | 11.6 | 34.9 | 0.1 | 28.6 | alto | 1 |
| 2025-03-25 | 74 | 255 | 34.2 | 19.4 | 28 | 13.5 | 39.2 | 0 | 32.4 | alto | 1 |
| 2025-03-26 | 84 | 187 | 33.5 | 19.2 | 34 | 12.6 | 38.9 | 0 | 32.1 | alto | 1 |
| 2025-03-27 | 52 | 188 | 34.4 | 19 | 28 | 11.2 | 32.8 | 0 | 31.4 | alto | 1 |
| 2025-03-28 | 23 | 71 | 33.6 | 18 | 29 | 10.8 | 28.1 | 0 | 31.5 | alto | 1 |
| 2025-03-29 | 82 | 332 | 35 | 19.1 | 21 | 11.6 | 33.1 | 0 | 36.5 | alto | 1 |
| 2025-03-30 | 106 | 310 | 37.7 | 18.7 | 21 | 13.5 | 37.4 | 0 | 40.5 | muy_alto | 1 |
| 2025-03-31 | 138 | 473 | 34.7 | 22.4 | 33 | 12.9 | 39.2 | 0 | 36.4 | alto | 1 |
| 2025-04-01 | 90 | 266 | 34.8 | 21.9 | 30 | 11.9 | 36 | 0 | 35.8 | alto | 1 |
| 2025-04-02 | 24 | 321 | 36.4 | 21.5 | 29 | 10.7 | 32 | 0 | 35.2 | alto | 1 |
| 2025-04-03 | 32 | 99 | 36.2 | 22.9 | 32 | 11.2 | 29.2 | 0 | 35.9 | alto | 1 |
| 2025-04-04 | 50 | 245 | 34.5 | 22.7 | 37 | 11.1 | 35.6 | 0.1 | 33 | alto | 1 |
| 2025-04-05 | 12 | 111 | 33.8 | 22.4 | 40 | 16.2 | 46.1 | 0.2 | 35.1 | alto | 1 |
| 2025-04-06 | 1 | 6 | 32.1 | 21.8 | 45 | 9.9 | 38.9 | 3.6 | 7.3 | bajo | 1 |
| 2025-04-07 | 0 | 0 | 32 | 19.8 | 44 | 6.8 | 24.5 | 0.3 | 15.5 | moderado | 1 |
| 2025-04-08 | 1 | 3 | 34.1 | 20.7 | 32 | 8 | 23 | 0 | 24.7 | alto | 1 |
| 2025-04-09 | 0 | 0 | 34.1 | 20.9 | 37 | 9.3 | 29.9 | 0 | 25.9 | alto | 1 |
| 2025-04-10 | 16 | 48 | 34.4 | 21.7 | 37 | 12.5 | 38.2 | 0.3 | 28.4 | alto | 1 |
| 2025-04-11 | 1 | 2 | 32.3 | 21.6 | 49 | 11.9 | 36.4 | 0.3 | 25.3 | alto | 0 |
| 2025-04-12 | 0 | 0 | 27.1 | 22 | 68 | 9.3 | 29.2 | 10.5 | 0.6 | muy_bajo | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 32,058ha
- GWIS perimeter (Copernicus)
- Duration
- 38days
- 4 Mar 2025 – 10 Apr 2025
- Municipalities hit
- 2
- districts
- Started on
- 4 Mar
- 2025
- Heat detections
- 1,330
- in a single hotspot: 51 MW
- Danger at start
- 20
- Moderate · FWI index
- Average daily power
- 122MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
4 Mar10 Apr
11 Apr 2025
How it evolved, day by day
4 Mar
13 Mar
21 Mar
31 Mar
6 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
38°high
46km/h · peak gust
21%lowest humidity
It had gone 6 days without rain (1 mm or more) when it started. Rain came after the fire: 10.5 mm on 12 Apr.
This area had burned before
97% of the perimeter overlaps earlier fires recorded since 2016: 12,855 ha in 2016, 7,882 ha in 2017, 9,927 ha in 2018, 16,080 ha in 2019, 10,618 ha in 2020, 13,855 ha in 2021, 9,320 ha in 2022, 9,333 ha in 2023, 15,842 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 31,152 ha that had burned before.
- 2,362 ha Khun Yuam fire, February 2020 2,850 ha in total; the hectares shown are those it shares with this fire
- 2,198 ha Khun Yuam fire, March 2018 2,604 ha in total; the hectares shown are those it shares with this fire
- 1,686 ha Khun Yuam fire, March 2019 3,087 ha in total; the hectares shown are those it shares with this fire
- 1,609 ha Mueang Mae Hong Son fire, March 2016 2,278 ha in total; the hectares shown are those it shares with this fire
- 1,549 ha Khun Yuam fire, March 2019 1,802 ha in total; the hectares shown are those it shares with this fire
- 1,383 ha Khun Yuam fire, March 2024 1,916 ha in total; the hectares shown are those it shares with this fire
- 1,353 ha Mueang Mae Hong Son fire, March 2019 1,520 ha in total; the hectares shown are those it shares with this fire
- 1,291 ha Mueang Mae Hong Son fire, March 2019 4,210 ha in total; the hectares shown are those it shares with this fire
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Bangkok boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
18,621 ha reached on 4 Mar8.0 %
-
Khun Yuam ขุนยวม13,981 ha reached on 15 Mar8.6 %
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 2025Built-up area16 ha
Residents≈ 1,200
Inside the perimeter there were about 16 hectares of built-up land and about 1,200 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) |
|---|---|---|---|---|---|
| 4 Mar | 31.7 °C | 32 % | 32 km/h | 0.0 mm | Moderate 20 |
| 5 Mar | 31.4 °C | 35 % | 33 km/h | 0.0 mm | Moderate 21 |
| 6 Mar | 32.1 °C | 31 % | 32 km/h | 0.0 mm | High 22 |
| 7 Mar | 34.7 °C | 26 % | 46 km/h | 0.0 mm | High 29 |
| 8 Mar | 31.1 °C | 44 % | 40 km/h | 0.0 mm | High 22 |
| 9 Mar | 31.8 °C | 40 % | 30 km/h | 0.0 mm | Moderate 21 |
| 10 Mar | 32.6 °C | 41 % | 22 km/h | 0.2 mm | Moderate 21 |
| 11 Mar | 33.5 °C | 37 % | 35 km/h | 0.0 mm | High 23 |
| 12 Mar | 31.6 °C | 44 % | 38 km/h | 0.5 mm | High 23 |
| 13 Mar | 34.4 °C | 30 % | 40 km/h | 0.0 mm | High 27 |
| 14 Mar | 34.2 °C | 29 % | 31 km/h | 0.0 mm | High 26 |
| 15 Mar | 35.1 °C | 28 % | 31 km/h | 0.0 mm | High 27 |
| 16 Mar | 34.8 °C | 30 % | 34 km/h | 0.0 mm | High 29 |
| 17 Mar | 35.5 °C | 29 % | 37 km/h | 0.0 mm | High 30 |
| 18 Mar | 34.4 °C | 35 % | 37 km/h | 0.0 mm | High 31 |
| 19 Mar | 31.2 °C | 45 % | 28 km/h | 0.4 mm | High 24 |
| 20 Mar | 31.7 °C | 39 % | 27 km/h | 0.0 mm | High 24 |
| 21 Mar | 31.2 °C | 41 % | 20 km/h | 0.0 mm | High 24 |
| 22 Mar | 33.1 °C | 39 % | 23 km/h | 0.0 mm | High 25 |
| 23 Mar | 33.6 °C | 40 % | 28 km/h | 0.0 mm | High 25 |
| 24 Mar | 34.4 °C | 32 % | 35 km/h | 0.1 mm | High 29 |
| 25 Mar | 34.2 °C | 28 % | 39 km/h | 0.0 mm | High 32 |
| 26 Mar | 33.5 °C | 34 % | 39 km/h | 0.0 mm | High 32 |
| 27 Mar | 34.4 °C | 28 % | 33 km/h | 0.0 mm | High 31 |
| 28 Mar | 33.6 °C | 29 % | 28 km/h | 0.0 mm | High 32 |
| 29 Mar | 35.0 °C | 21 % | 33 km/h | 0.0 mm | High 36 |
| 30 Mar | 37.7 °C | 21 % | 37 km/h | 0.0 mm | Very high 40 |
| 31 Mar | 34.7 °C | 33 % | 39 km/h | 0.0 mm | High 36 |
| 1 Apr | 34.8 °C | 30 % | 36 km/h | 0.0 mm | High 36 |
| 2 Apr | 36.4 °C | 29 % | 32 km/h | 0.0 mm | High 35 |
| 3 Apr | 36.2 °C | 32 % | 29 km/h | 0.0 mm | High 36 |
| 4 Apr | 34.5 °C | 37 % | 36 km/h | 0.1 mm | High 33 |
| 5 Apr | 33.8 °C | 40 % | 46 km/h | 0.2 mm | High 35 |
| 6 Apr | 32.1 °C | 45 % | 39 km/h | 3.6 mm | Low 7 |
| 7 Apr | 32.0 °C | 44 % | 24 km/h | 0.3 mm | Moderate 16 |
| 8 Apr | 34.1 °C | 32 % | 23 km/h | 0.0 mm | High 25 |
| 9 Apr | 34.1 °C | 37 % | 30 km/h | 0.0 mm | High 26 |
| 10 Apr | 34.4 °C | 37 % | 38 km/h | 0.3 mm | High 28 |
| 11 Apr after | 32.3 °C | 49 % | 36 km/h | 0.3 mm | High 25 |
| 12 Apr after | 27.1 °C | 68 % | 29 km/h | 10.5 mm | Very low 1 |
Its twins: fires that started in the same weather
It started with an FWI of 19.9, a minimum humidity of 32% and 6 days without rain. Fires in the area that started in weather like this since 2016: 48.
FWI at the start
19.9
Minimum humidity
32 %
Days without rain
6
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Mueang Mae Hong Son fire, 4 March 2025
32,058 ha
38 days
FWI 19.9
Min. humidity 32 %
Mueang Mae Hong Son fire, March 2022
1,163 ha
4 days
FWI 19.8
Min. humidity 31 %
11 km away, in 2022
First rain (1 mm or more) after it ended: 1.6 mm on 2 Apr.
Mese fire, March 2016
5,303 ha
15 days
FWI 19.5
Min. humidity 33 %
76 km away, in 2016
First rain (1 mm or more) after it ended: none in the following ten days.
Mawkmai fire, March 2016
6,969 ha
10 days
FWI 20.8
Min. humidity 31 %
86 km away, in 2016
First rain (1 mm or more) after it ended: none in the following ten days.
Mese fire, February 2021
2,555 ha
5 days
FWI 18.0
Min. humidity 31 %
52 km away, in 2021
First rain (1 mm or more) after it ended: none in the following ten days.
Samoeng fire, March 2024
4,409 ha
11 days
FWI 18.3
Min. humidity 32 %
67 km away, in 2024
First rain (1 mm or more) after it ended: 1.0 mm on 9 Apr.
What happened to them
- 12 days
- median duration
- 2,267 ha
- median area
- 100 %
- went past 1,000 ha
- 3.7 mm
- rain at the end (median; 16 of 48 had it)
It was 14.1 times larger than the median of its twins and lasted 38 days, against 12 days.
None of its 48 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. In 32 of 48, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.7 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
10.5 mmfirst rain
12 Apr2 days after it ended
46km/h · max. gust
It was considered over on 10 Apr, and on 12 Apr 10.5 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 16 of 48, with a median of 3.7 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 25 Feb 2025
After · 17 Apr 2025
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 · CopernicusOn 4 April 2025 the air beside the fire reached 110 µg/m³ of PM2.5. That day averaged 76: 5.1 times the WHO daily guideline (15).
PM2.5 peak110 µg/m³
Days over the guideline33 days
PM10112 µg/m³
Optical depth1.46
WHO 15
5 Mar12 Mar19 Mar26 Mar2 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 · 1,330Every 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
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 4 March 2025 to 10 April 2025 (38 days). The perimeter dates it from 7 March 2025 to 4 April 2025.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 32,058 hectares (320.6 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Mueang Mae Hong Son (18,621 ha, 8.0 %); Khun Yuam (13,981 ha, 8.6 %).
- What was the weather like?
- During the fire the temperature reached 37.7 °C, humidity dropped to 21 % and gusts hit 46 km/h. The fire danger index (FWI) reached 40, 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.
- 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: 48. Their median duration was 12 days and their median area 2,267 ha; 100 % went past 1,000 ha. None of its 48 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. In 32 of 48, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.7 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: 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.
- Last day with fire: 4 April 2025 → 10 April 2025.
- Start date: 7 March 2025 → 4 March 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
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 7 March 2025 to 4 April 2025. 1,330 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.
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.