Pai fire, 24 March 2026 Pai
The fire started on 24 March 2026 in Pai, Thailand, and satellites saw it burning for 26 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 22,763 hectares from heat detections, spread across a single municipality.
It is the 12th largest in Mae Hong Son Province since 2016 (of 668 with a page). Number 25 in Thailand in 2026, of 880.
- Burnt area
- 22,763ha
- GWIS perimeter (Copernicus)
- Duration
- 26days
- 24 Mar 2026 – 18 Apr 2026
- Municipalities hit
- 1
- districts
- Started on
- 24 Mar
- 2026
- Heat detections
- 536
- in a single hotspot: 109 MW
- Danger at start
- 22
- High · FWI index
- Energy released
- 1.8GW
- sum of detected power
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone 9 days without rain (1 mm or more) when it started. Rain came after the fire: 2.1 mm on 25 Apr.
This area had burned before
90% of the perimeter overlaps earlier fires recorded since 2016: 6,396 ha in 2016, 8,703 ha in 2017, 3,131 ha in 2018, 7,575 ha in 2019, 12,404 ha in 2020, 4,192 ha in 2021, 771 ha in 2022, 5,660 ha in 2023, 10,228 ha in 2024, 3,318 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 20,589 ha that had burned before.
- 5,325 ha Pai fire, March 2017 6,340 ha in total; the hectares shown are those it shares with this fire
- 4,995 ha Pai fire, February 2024 5,313 ha in total; the hectares shown are those it shares with this fire
- 3,465 ha Pai fire, March 2020 3,726 ha in total; the hectares shown are those it shares with this fire
- 2,429 ha Pai fire, March 2016 2,719 ha in total; the hectares shown are those it shares with this fire
- 1,620 ha Pai fire, March 2019 2,326 ha in total; the hectares shown are those it shares with this fire
- 854 ha Pai fire, March 2020 1,428 ha in total; the hectares shown are those it shares with this fire
- 682 ha Pai fire, March 2020 1,716 ha in total; the hectares shown are those it shares with this fire
- 648 ha Pai fire, March 2023 1,023 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Pai where it started22,896 ha reached on 24 Mar10.0 %
Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.
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) |
|---|---|---|---|---|---|
| 24 Mar | 34.1 °C | 26 % | 34 km/h | 0.0 mm | High 22 |
| 25 Mar | 34.2 °C | 24 % | 38 km/h | 0.0 mm | High 25 |
| 26 Mar | 34.7 °C | 27 % | 36 km/h | 0.0 mm | High 25 |
| 27 Mar | 35.1 °C | 27 % | 41 km/h | 0.0 mm | High 27 |
| 28 Mar | 35.9 °C | 21 % | 46 km/h | 0.0 mm | High 31 |
| 29 Mar | 35.4 °C | 21 % | 50 km/h | 0.0 mm | High 33 |
| 30 Mar | 35.0 °C | 27 % | 44 km/h | 0.0 mm | High 32 |
| 31 Mar | 35.9 °C | 30 % | 38 km/h | 0.0 mm | High 30 |
| 1 Apr | 35.7 °C | 31 % | 33 km/h | 0.0 mm | High 30 |
| 2 Apr | 36.1 °C | 28 % | 40 km/h | 0.0 mm | High 32 |
| 3 Apr | 37.0 °C | 26 % | 36 km/h | 0.0 mm | High 32 |
| 4 Apr | 35.7 °C | 33 % | 36 km/h | 0.2 mm | High 31 |
| 5 Apr | 35.6 °C | 37 % | 37 km/h | 0.0 mm | High 29 |
| 6 Apr | 35.1 °C | 37 % | 31 km/h | 0.1 mm | High 28 |
| 7 Apr | 34.8 °C | 37 % | 42 km/h | 0.1 mm | High 31 |
| 8 Apr | 35.6 °C | 28 % | 40 km/h | 0.1 mm | High 32 |
| 9 Apr | 34.2 °C | 33 % | 45 km/h | 0.0 mm | High 33 |
| 10 Apr | 34.1 °C | 32 % | 48 km/h | 0.0 mm | High 34 |
| 11 Apr | 35.0 °C | 30 % | 45 km/h | 0.0 mm | High 34 |
| 12 Apr | 36.1 °C | 25 % | 38 km/h | 0.0 mm | High 34 |
| 13 Apr | 36.5 °C | 28 % | 35 km/h | 0.0 mm | High 34 |
| 14 Apr | 36.6 °C | 29 % | 31 km/h | 0.0 mm | High 33 |
| 15 Apr | 36.6 °C | 30 % | 37 km/h | 0.0 mm | High 36 |
| 16 Apr | 35.4 °C | 30 % | 30 km/h | 0.0 mm | High 34 |
| 17 Apr | 36.0 °C | 31 % | 26 km/h | 0.0 mm | High 33 |
| 18 Apr | 35.2 °C | 37 % | 29 km/h | 0.1 mm | High 32 |
| 19 Apr after | 35.6 °C | 32 % | 44 km/h | 0.2 mm | High 36 |
| 20 Apr after | 34.5 °C | 37 % | 36 km/h | 0.0 mm | High 33 |
| 21 Apr after | 36.3 °C | 36 % | 36 km/h | 0.2 mm | High 33 |
| 22 Apr after | 37.1 °C | 31 % | 37 km/h | 0.0 mm | High 33 |
| 23 Apr after | 34.7 °C | 40 % | 35 km/h | 0.2 mm | High 29 |
| 24 Apr after | 36.7 °C | 34 % | 25 km/h | 0.1 mm | High 29 |
| 25 Apr after | 33.4 °C | 45 % | 35 km/h | 2.1 mm | Moderate 12 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 17 April 2026 the air beside the fire reached 122 µg/m³ of PM2.5. That day averaged 62: 4.1 times the WHO daily guideline (15).
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 · 536Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Pai fire last?
- GWIS (Copernicus) dates it between 24 March 2026 and 18 April 2026: 26 days between the first and last heat detection of the perimeter.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 22,763 hectares (227.6 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Pai (22,896 ha, 10.0 %).
- What was the weather like?
- During the fire the temperature reached 37.0 °C, humidity dropped to 21 % and gusts hit 50 km/h. The fire danger index (FWI) reached 36, 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
Satellite cross-check
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
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.