Li fire, 23 March 2026 Li, Sam Ngao
The fire started on 23 March 2026 in Li, Thailand, and satellites saw it burning for 33 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 20,120 hectares from heat detections, spread across 2 municipalities.
It is the 5th largest in Chiang Mai Province since 2016 (of 463 with a page). Number 31 in Thailand in 2026, of 880.
The power measured by the satellite is low (16.1 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
- Burnt area
- 20,120ha
- GWIS perimeter (Copernicus)
- Duration
- 33days
- 23 Mar 2026 – 24 Apr 2026
- Municipalities hit
- 2
- districts
- Started on
- 23 Mar
- 2026
- Heat detections
- 586
- in a single hotspot: 16 MW
- Danger at start
- 26
- 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 8 days without rain (1 mm or more) when it started. Rain came after the fire: 3.7 mm on 25 Apr.
This area had burned before
96% of the perimeter overlaps earlier fires recorded since 2016: 5,389 ha in 2016, 8,231 ha in 2017, 3,349 ha in 2018, 5,253 ha in 2019, 8,484 ha in 2020, 9,534 ha in 2021, 560 ha in 2022, 8,163 ha in 2023, 7,692 ha in 2024, 1,811 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 19,252 ha that had burned before.
- 3,753 ha Li fire, March 2024 5,674 ha in total; the hectares shown are those it shares with this fire
- 3,337 ha Li fire, February 2021 3,710 ha in total; the hectares shown are those it shares with this fire
- 2,937 ha Li fire, January 2020 3,006 ha in total; the hectares shown are those it shares with this fire
- 2,077 ha Li fire, March 2017 2,743 ha in total; the hectares shown are those it shares with this fire
- 1,944 ha Li fire, February 2023 2,612 ha in total; the hectares shown are those it shares with this fire
- 1,568 ha Li fire, February 2021 2,851 ha in total; the hectares shown are those it shares with this fire
- 1,256 ha Li fire, March 2024 1,283 ha in total; the hectares shown are those it shares with this fire
- 1,173 ha Li fire, March 2018 1,431 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Li where it started13,974 ha reached on 23 Mar7.7 %
-
6,246 ha reached on 23 Mar2.3 %
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) |
|---|---|---|---|---|---|
| 22 Mar | 32.9 °C | 36 % | 34 km/h | 0.0 mm | High 26 |
| 23 Mar | 33.8 °C | 25 % | 31 km/h | 0.0 mm | High 28 |
| 24 Mar | 34.3 °C | 25 % | 29 km/h | 0.0 mm | High 28 |
| 25 Mar | 34.4 °C | 27 % | 29 km/h | 0.0 mm | High 29 |
| 26 Mar | 35.5 °C | 25 % | 26 km/h | 0.0 mm | High 29 |
| 27 Mar | 35.3 °C | 25 % | 32 km/h | 0.0 mm | High 31 |
| 28 Mar | 35.0 °C | 30 % | 30 km/h | 0.0 mm | High 31 |
| 29 Mar | 35.2 °C | 27 % | 33 km/h | 0.1 mm | High 32 |
| 30 Mar | 35.4 °C | 28 % | 28 km/h | 0.0 mm | High 32 |
| 31 Mar | 35.3 °C | 30 % | 24 km/h | 0.0 mm | High 31 |
| 1 Apr | 35.1 °C | 31 % | 23 km/h | 0.0 mm | High 32 |
| 2 Apr | 35.9 °C | 29 % | 28 km/h | 0.0 mm | High 32 |
| 3 Apr | 36.3 °C | 28 % | 34 km/h | 0.0 mm | High 33 |
| 4 Apr | 34.0 °C | 36 % | 30 km/h | 0.0 mm | High 31 |
| 5 Apr | 35.3 °C | 35 % | 31 km/h | 0.0 mm | High 31 |
| 6 Apr | 35.1 °C | 35 % | 27 km/h | 0.1 mm | High 31 |
| 7 Apr | 35.2 °C | 34 % | 35 km/h | 0.0 mm | High 35 |
| 8 Apr | 35.8 °C | 28 % | 37 km/h | 0.0 mm | High 35 |
| 9 Apr | 34.9 °C | 27 % | 36 km/h | 0.0 mm | High 35 |
| 10 Apr | 35.7 °C | 27 % | 34 km/h | 0.0 mm | High 34 |
| 11 Apr | 35.1 °C | 30 % | 38 km/h | 0.0 mm | High 36 |
| 12 Apr | 36.0 °C | 29 % | 31 km/h | 0.0 mm | High 34 |
| 13 Apr | 36.3 °C | 30 % | 33 km/h | 0.1 mm | High 34 |
| 14 Apr | 36.5 °C | 28 % | 25 km/h | 0.0 mm | High 33 |
| 15 Apr | 36.8 °C | 19 % | 36 km/h | 0.0 mm | Very high 42 |
| 16 Apr | 37.2 °C | 22 % | 27 km/h | 0.0 mm | Very high 38 |
| 17 Apr | 37.0 °C | 25 % | 26 km/h | 0.0 mm | High 37 |
| 18 Apr | 36.5 °C | 28 % | 29 km/h | 0.0 mm | Very high 38 |
| 19 Apr | 36.7 °C | 24 % | 38 km/h | 0.0 mm | Very high 43 |
| 20 Apr | 35.8 °C | 32 % | 34 km/h | 0.0 mm | Very high 38 |
| 21 Apr | 35.4 °C | 38 % | 27 km/h | 0.1 mm | High 32 |
| 22 Apr | 36.7 °C | 32 % | 28 km/h | 0.0 mm | High 33 |
| 23 Apr | 34.6 °C | 38 % | 32 km/h | 0.0 mm | High 32 |
| 24 Apr | 35.9 °C | 35 % | 20 km/h | 0.0 mm | High 31 |
| 25 Apr after | 30.7 °C | 51 % | 31 km/h | 3.7 mm | Low 6 |
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 26 March 2026 the air beside the fire reached 91 µg/m³ of PM2.5. That day averaged 53: 3.5 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 · 586Every 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 Li fire last?
- GWIS (Copernicus) dates it between 23 March 2026 and 24 April 2026: 33 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 20,120 hectares (201.2 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Li (13,974 ha, 7.7 %); Sam Ngao (6,246 ha, 2.3 %).
- What was the weather like?
- During the fire the temperature reached 37.2 °C, humidity dropped to 19 % and gusts hit 38 km/h. The fire danger index (FWI) reached 43, 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
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.