How long did the Mae Chaem fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 22 March 2020 to 12 April 2020 (22 days). The perimeter dates it from 27 March 2020 to 8 April 2020.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 8,068 hectares (80.7 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Mae Chaem (7,464 ha, 2.7 %); Samoeng (658 ha, 0.6 %).

What was the weather like?

During the fire the temperature reached 35.4 °C, humidity dropped to 20 % and gusts hit 49 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.

TH · Thailand · 2020-03-22 → 2020-04-12

Mae Chaem fire, 22 March 2020 แม่แจ่ม · Mae Chaem, Samoeng

Out · last detection 13 Apr 2020, 18:54 UTC

The fire started on 22 March 2020 in Mae Chaem, Thailand, and satellites saw it burning for 22 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 8,068 hectares from heat detections, spread across 2 municipalities.

It is the 16th largest in Chiang Mai Province since 2016 (of 399 with a page). Number 15 in Thailand in 2020, of 457.

Compare with…

Suggestions: Mae Chaem · 2016 Hang Dong · 2016 Samoeng · 2020 Samoeng · 2026

Burnt area: 8,068ha; GWIS perimeter (Copernicus)
Duration: 22days; 22 Mar 2020 – 12 Apr 2020
Municipalities hit: 2; districts
Started on: 22 Mar; 2020
Heat detections: 350; in a single hotspot: 35 MW
Danger at start: 30; High · FWI index
Average daily power: 82MW; detected power per day, on average

HOTSPOTS BY DAY 22 Mar12 Apr

Play back 13 Apr 2020

How it evolved, day by day

22 Mar 25 Mar 28 Mar 31 Mar 2 Apr 3 Apr 6 Apr 12 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

35°high

49km/h · peak gust

20%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 5.8 mm on 14 Apr.

This area had burned before

41% of the perimeter overlaps earlier fires recorded since 2016: 2,275 ha in 2016, 111 ha in 2017, 1,314 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 3,313 ha that had burned before.

834 ha Mae Chaem fire, April 2016 2,171 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 5.1% of the area of London (81 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

Mae Chaem แม่แจ่ม where it started

7,464 ha reached on 22 Mar

2.7 %
Samoeng สะเมิง

658 ha reached on 22 Mar

0.6 %

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 2020

Built-up area1.6 ha

Residents≈ 300

Inside the perimeter there were about 1.6 hectares of built-up land and about 300 residents (GHSL 2020, 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.

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)
22 Mar	31.5 °C	28 %	39 km/h	0.3 mm	High 30
23 Mar	31.9 °C	27 %	37 km/h	0.0 mm	High 31
24 Mar	31.7 °C	27 %	47 km/h	0.0 mm	High 34
25 Mar	32.2 °C	25 %	49 km/h	0.0 mm	High 36
26 Mar	32.5 °C	27 %	44 km/h	0.0 mm	High 35
27 Mar	33.4 °C	27 %	31 km/h	0.0 mm	High 31
28 Mar	34.0 °C	29 %	30 km/h	0.0 mm	High 32
29 Mar	34.4 °C	25 %	31 km/h	0.0 mm	High 33
30 Mar	34.8 °C	32 %	30 km/h	0.0 mm	High 33
31 Mar	35.4 °C	29 %	30 km/h	0.0 mm	High 33
1 Apr	35.4 °C	21 %	37 km/h	0.0 mm	High 38
2 Apr	34.7 °C	23 %	44 km/h	0.0 mm	Very high 40
3 Apr	35.3 °C	20 %	36 km/h	0.0 mm	Very high 38
4 Apr	35.1 °C	23 %	29 km/h	0.0 mm	High 36
5 Apr	34.7 °C	24 %	34 km/h	0.0 mm	High 38
6 Apr	32.8 °C	37 %	43 km/h	0.4 mm	High 35
7 Apr	34.0 °C	25 %	41 km/h	0.0 mm	High 36
8 Apr	33.7 °C	27 %	26 km/h	0.0 mm	High 32
9 Apr	33.7 °C	25 %	32 km/h	0.0 mm	High 34
10 Apr	34.1 °C	23 %	41 km/h	0.0 mm	High 37
11 Apr	33.7 °C	32 %	22 km/h	0.2 mm	High 32
12 Apr	33.9 °C	31 %	29 km/h	0.0 mm	High 33
13 Apr after	35.1 °C	20 %	38 km/h	0.1 mm	Very high 39
14 Apr after	29.7 °C	55 %	32 km/h	5.8 mm	Very low 4

Before and after, from space

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

↔

Before · 15 Mar 2020

After · 19 Apr 2020

Before After

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

Detections table · 350Every 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

All fires in Thailand ›

Frequently asked questions

How long did the Mae Chaem fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 22 March 2020 to 12 April 2020 (22 days). The perimeter dates it from 27 March 2020 to 8 April 2020.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 8,068 hectares (80.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Mae Chaem (7,464 ha, 2.7 %); Samoeng (658 ha, 0.6 %).
What was the weather like?: During the fire the temperature reached 35.4 °C, humidity dropped to 20 % and gusts hit 49 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.

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

NASA FIRMS ↗
GWIS · Copernicus ↗

History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

26 October 2026 Last day with fire: 8 April 2020 → 12 April 2020.
26 October 2026 Start date: 27 March 2020 → 22 March 2020.

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?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

What really happened?

Your connection to the fire (optional) Email (optional)

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; 4 polygons grouped in this page.
Dates adjusted with the VIIRS detections inside the perimeter, which said 27 March 2020 to 8 April 2020. 350 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 2020, 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.

Where it burned