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Mae Chai fire, 27 March 2026 แม่ใจ · Mae Chai, Mueang Phayao

Out · last detection 15 Apr 2026, 18:43 UTC

The fire started on 27 March 2026 in Mae Chai, Thailand, and satellites saw it burning for 23 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,897 hectares from heat detections, spread across 2 municipalities.

It is the 27th largest in Phayao Province since 2016 (of 110 with a page). Number 203 in Thailand in 2026, of 689.

The power measured by the satellite is low (10.0 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Mae Chai · 2016Mae Lao · 2023Wiang Pa Pao · 2026Chae Hom · 2026

Burnt area
2,897ha
GWIS perimeter (Copernicus)
Duration
23days
27 Mar 2026 – 18 Apr 2026
Municipalities hit
2
districts
Started on
27 Mar
2026
Heat detections
66
in a single hotspot: 10 MW
Danger at start
23
High · FWI index
Average daily power
12MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 27 Mar18 Apr
15 Apr 2026

How it evolved, day by day

28 Mar 2026 · 13 MW · 5 29 Mar 2026 · 25 MW · 6 30 Mar 2026 · 25 MW · 10 31 Mar 2026 · 6 MW · 5 1 Apr 2026 · 2 MW · 1 2 Apr 2026 · 7 MW · 3 3 Apr 2026 · 5 MW · 2 5 Apr 2026 · 7 MW · 2 7 Apr 2026 · 1 MW · 1 8 Apr 2026 · 7 MW · 6 9 Apr 2026 · 36 MW · 11 13 Apr 2026 · 7 MW · 3 14 Apr 2026 · 24 MW · 8 15 Apr 2026 · 8 MW · 3
28 Mar 30 Mar 1 Apr 3 Apr 7 Apr 9 Apr 14 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

37°high
41km/h · peak gust
23%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started.

This area had burned before

93% of the perimeter overlaps earlier fires recorded since 2016: 1,507 ha in 2016, 2,080 ha in 2019, 790 ha in 2020, 391 ha in 2021, 1,140 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 2,686 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1.8% of the area of London (29 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. Mae Chai แม่ใจ where it started
    2,878 ha reached on 28 Mar
    9.7 %
  2. Mueang Phayao เมืองพะเยา
    34 ha
    0.0 %

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 area0.20 ha
Residents≈ 20

Inside the perimeter there were about 0.20 hectares of built-up land and about 20 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)
20 Mar 34.6 °C 31 % 20 km/h 0.0 mm High 23
21 Mar 35.4 °C 35 % 31 km/h 0.5 mm High 26
22 Mar 34.9 °C 30 % 39 km/h 0.0 mm High 29
23 Mar 35.6 °C 25 % 31 km/h 0.0 mm High 29
24 Mar 35.9 °C 23 % 26 km/h 0.0 mm High 29
25 Mar 35.8 °C 23 % 32 km/h 0.0 mm High 32
26 Mar 36.1 °C 25 % 22 km/h 0.0 mm High 29
27 Mar 36.3 °C 25 % 32 km/h 0.0 mm High 33
28 Mar 36.6 °C 26 % 34 km/h 0.0 mm High 35
29 Mar 36.3 °C 25 % 41 km/h 0.0 mm High 37
30 Mar 36.0 °C 29 % 30 km/h 0.0 mm High 34
31 Mar 36.6 °C 31 % 24 km/h 0.0 mm High 33
1 Apr 36.3 °C 35 % 22 km/h 0.0 mm High 31
2 Apr 36.9 °C 32 % 28 km/h 0.0 mm High 33
3 Apr 37.2 °C 31 % 23 km/h 0.0 mm High 32
4 Apr 36.0 °C 37 % 24 km/h 0.0 mm High 30
5 Apr 37.0 °C 37 % 24 km/h 0.0 mm High 31
6 Apr 36.2 °C 38 % 22 km/h 0.0 mm High 29
7 Apr 36.3 °C 37 % 26 km/h 0.0 mm High 32
8 Apr 37.0 °C 29 % 31 km/h 0.0 mm High 33
9 Apr 36.4 °C 32 % 25 km/h 0.0 mm High 32
10 Apr 36.9 °C 28 % 35 km/h 0.0 mm High 36
11 Apr 36.5 °C 29 % 33 km/h 0.0 mm High 35
12 Apr 37.0 °C 25 % 22 km/h 0.0 mm High 34
13 Apr 37.3 °C 31 % 25 km/h 0.0 mm High 34
14 Apr 37.5 °C 32 % 22 km/h 0.0 mm High 35
15 Apr 37.9 °C 24 % 32 km/h 0.0 mm Very high 40
16 Apr 36.9 °C 30 % 18 km/h 0.0 mm High 36
17 Apr 36.9 °C 34 % 19 km/h 0.0 mm High 34
18 Apr 36.2 °C 38 % 20 km/h 0.0 mm High 32
19 Apr after 36.8 °C 33 % 29 km/h 0.3 mm High 34
20 Apr after 35.6 °C 40 % 31 km/h 0.0 mm High 32
21 Apr after 36.9 °C 38 % 29 km/h 0.0 mm High 32
22 Apr after 37.3 °C 37 % 26 km/h 0.0 mm High 32

Before and after, from space

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

Before · 20 Mar 2026
After · 25 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 5 April 2026 the air beside the fire reached 107 µg/m³ of PM2.5. That day averaged 77: 5.1 times the WHO daily guideline (15).

PM2.5 peak107 µg/m³
Days over the guideline22 days
PM10122 µg/m³
Optical depth1.79
25262728293031123456789101112131415
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 · 66Every 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 Mae Chai fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 27 March 2026 to 18 April 2026 (23 days). The perimeter dates it from 27 March 2026 to 12 April 2026.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,897 hectares (29.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Mae Chai (2,878 ha, 9.7 %); Mueang Phayao (34 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 37.2 °C, humidity dropped to 23 % and gusts hit 41 km/h. The fire danger index (FWI) reached 37, 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 12 April 2026 → 18 April 2026.

RSS Changes to this page

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; 2 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 27 March 2026 to 12 April 2026. 66 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.