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Li fire, 20 March 2026 Li, Doi Tao, Sam Ngao

Out · last detection 13 Apr 2026, 06:50 UTC

The fire started on 20 March 2026 in Li, Thailand, and satellites saw it burning for 24 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 28,586 hectares from heat detections, spread across 4 municipalities.

It is the 3th largest in Chiang Mai Province since 2016 (of 463 with a page). Number 21 in Thailand in 2026, of 880.

The power measured by the satellite is low (20.8 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
28,586ha
GWIS perimeter (Copernicus)
Duration
24days
20 Mar 2026 – 12 Apr 2026
Municipalities hit
4
districts
Started on
20 Mar
2026
Heat detections
1,091
in a single hotspot: 21 MW
Danger at start
20
Moderate · FWI index
Energy released
3.5GW
sum of detected power

Where it burned

13 Apr 2026
HOTSPOTS BY DAY 20 Mar12 Apr

How it evolved, day by day

20212223242526272829303112345678910111213

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

The weather it burned in

36°high
38km/h · peak gust
25%lowest humidity

It had gone 4 days without rain (1 mm or more) when it started.

This area had burned before

89% of the perimeter overlaps earlier fires recorded since 2016: 3,794 ha in 2016, 9,291 ha in 2017, 4,266 ha in 2018, 9,826 ha in 2019, 9,743 ha in 2020, 11,387 ha in 2021, 11,932 ha in 2023, 9,446 ha in 2024, 739 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 25,470 ha that had burned before.

What happened to each town

  1. Li where it started
    21,825 ha reached on 20 Mar
    12 %
  2. Doi Tao
    6,087 ha reached on 22 Mar
    7.1 %
  3. Sam Ngao
    638 ha reached on 27 Mar
    0.2 %
  4. Mae Phrik
    181 ha reached on 25 Mar
    0.3 %

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)
18 Mar 32.8 °C 29 % 14 km/h 0.0 mm Moderate 20
19 Mar 33.3 °C 29 % 18 km/h 0.0 mm High 22
20 Mar 33.5 °C 30 % 21 km/h 0.0 mm High 24
21 Mar 33.3 °C 33 % 26 km/h 0.0 mm High 25
22 Mar 32.5 °C 36 % 34 km/h 0.0 mm High 27
23 Mar 33.5 °C 25 % 31 km/h 0.0 mm High 28
24 Mar 34.0 °C 25 % 29 km/h 0.0 mm High 29
25 Mar 34.1 °C 27 % 29 km/h 0.0 mm High 29
26 Mar 35.2 °C 25 % 26 km/h 0.0 mm High 30
27 Mar 34.9 °C 25 % 32 km/h 0.0 mm High 32
28 Mar 34.6 °C 30 % 30 km/h 0.0 mm High 31
29 Mar 34.9 °C 27 % 33 km/h 0.1 mm High 33
30 Mar 35.1 °C 28 % 28 km/h 0.0 mm High 32
31 Mar 34.9 °C 30 % 24 km/h 0.0 mm High 31
1 Apr 34.7 °C 31 % 23 km/h 0.0 mm High 32
2 Apr 35.5 °C 29 % 28 km/h 0.0 mm High 32
3 Apr 35.9 °C 28 % 34 km/h 0.0 mm High 33
4 Apr 33.7 °C 36 % 30 km/h 0.0 mm High 31
5 Apr 35.0 °C 35 % 31 km/h 0.0 mm High 31
6 Apr 34.8 °C 35 % 27 km/h 0.1 mm High 31
7 Apr 34.8 °C 33 % 35 km/h 0.0 mm High 35
8 Apr 35.4 °C 28 % 37 km/h 0.0 mm High 35
9 Apr 34.6 °C 27 % 36 km/h 0.0 mm High 34
10 Apr 35.4 °C 27 % 34 km/h 0.0 mm High 34
11 Apr 34.7 °C 30 % 38 km/h 0.0 mm High 36
12 Apr 35.6 °C 29 % 31 km/h 0.0 mm High 34
13 Apr after 35.9 °C 30 % 33 km/h 0.1 mm High 34
14 Apr after 36.2 °C 28 % 25 km/h 0.0 mm High 33
15 Apr after 36.4 °C 19 % 36 km/h 0.0 mm Very high 42
16 Apr after 36.8 °C 22 % 27 km/h 0.0 mm Very high 38
17 Apr after 36.7 °C 25 % 26 km/h 0.0 mm High 37
18 Apr after 36.1 °C 28 % 29 km/h 0.0 mm Very high 38
19 Apr after 36.4 °C 24 % 38 km/h 0.0 mm Very high 43
20 Apr after 35.4 °C 32 % 34 km/h 0.0 mm High 38
21 Apr after 35.1 °C 38 % 27 km/h 0.1 mm High 32
22 Apr after 36.4 °C 32 % 28 km/h 0.0 mm High 33

Before and after, from space

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

Before · 13 Mar 2026
After · 19 Apr 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 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).

PM2.5 peak91 µg/m³
Days over the guideline25 days
PM1093 µg/m³
Optical depth1.39
1819202122232425262728293031123456789101112131415
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 · 1,091Every 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 Li fire last?
GWIS (Copernicus) dates it between 20 March 2026 and 12 April 2026: 24 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 28,586 hectares (285.9 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 4 municipalities: Li (21,825 ha, 12 %); Doi Tao (6,087 ha, 7.1 %); Sam Ngao (638 ha, 0.2 %); Mae Phrik (181 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 35.9 °C, humidity dropped to 25 % and gusts hit 38 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
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.

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.