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TH · Thailand · –

Mae Wong fire, 21 February 2023 แม่วงก์ · Mae Wong, Pang Sila Thong

Out · last detection 28 Feb 2023, 06:18 UTC

The fire started on 21 February 2023 in Mae Wong, Thailand, and satellites saw it burning for 8 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,059 hectares from heat detections, spread across 2 municipalities.

It is the 30th largest in Nakhon Sawan Province since 2016 (of 32 with a page). Number 338 in Thailand in 2023, of 369.

The power measured by the satellite is low (11.6 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
1,059ha
GWIS perimeter (Copernicus)
Duration
8days
21 Feb 2023 – 28 Feb 2023
Municipalities hit
2
districts
Started on
21 Feb
2023
Heat detections
34
in a single hotspot: 12 MW
Danger at start
14
Moderate · FWI index
Average daily power
21MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Feb28 Feb
28 Feb 2023

How it evolved, day by day

21 Feb 2023 · 6 MW · 4 22 Feb 2023 · 65 MW · 18 23 Feb 2023 · 28 MW · 10 24 Feb 2023 · 0 MW · 1 28 Feb 2023 · 7 MW · 1
21 Feb 22 Feb 23 Feb 24 Feb 28 Feb

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

The weather it burned in

33°high
40km/h · peak gust
41%lowest humidity

It had gone 5 days without rain (1 mm or more) when it started.

This area had burned before

75% of the perimeter overlaps earlier fires recorded since 2016: 103 ha in 2016, 44 ha in 2017, 92 ha in 2018, 347 ha in 2019, 36 ha in 2020, 680 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 791 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 0.7% of the area of London (11 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 Wong แม่วงก์ where it started
    1,064 ha reached on 21 Feb
    1.1 %
  2. Pang Sila Thong ปางศิลาทอง
    2 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 area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (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)
21 Feb 30.8 °C 52 % 26 km/h 0.0 mm Moderate 14
22 Feb 31.0 °C 50 % 29 km/h 0.0 mm Moderate 15
23 Feb 32.7 °C 43 % 30 km/h 0.0 mm Moderate 17
24 Feb 32.8 °C 41 % 28 km/h 0.0 mm Moderate 18
25 Feb 29.6 °C 50 % 37 km/h 0.0 mm Moderate 19
26 Feb 27.7 °C 48 % 40 km/h 0.0 mm Moderate 20
27 Feb 27.8 °C 47 % 34 km/h 0.0 mm Moderate 19
28 Feb 30.6 °C 42 % 27 km/h 0.0 mm Moderate 18
1 Mar after 32.3 °C 38 % 30 km/h 0.0 mm Moderate 20
2 Mar after 32.1 °C 40 % 34 km/h 0.0 mm High 21
3 Mar after 31.6 °C 45 % 28 km/h 0.0 mm Moderate 21
4 Mar after 30.3 °C 47 % 33 km/h 0.0 mm Moderate 21
5 Mar after 30.4 °C 48 % 29 km/h 0.0 mm Moderate 20
6 Mar after 31.2 °C 46 % 29 km/h 0.0 mm High 22
7 Mar after 32.7 °C 43 % 28 km/h 0.0 mm Moderate 21
8 Mar after 34.1 °C 38 % 26 km/h 0.0 mm High 22
9 Mar after 33.1 °C 49 % 32 km/h 0.0 mm High 23
10 Mar after 33.5 °C 49 % 28 km/h 0.0 mm High 22

Its twins: fires that started in the same weather

It started with an FWI of 14.3, a minimum humidity of 52% and 5 days without rain. Fires in the area that started in weather like this since 2016: 17.

FWI at the start 14.3
Minimum humidity 52 %
Days without rain 5
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Myawaddy fire, March 2018
5,525 ha 8 days FWI 14.0 Min. humidity 52 % 72 km away, in 2018

First rain (1 mm or more) after it ended: 5.8 mm on 23 Mar.

What happened to them

8 days
median duration
1,756 ha
median area
100 %
went past 1,000 ha
2.3 mm
rain at the end (median; 12 of 17 had it)

It stayed below its twins: 1,059 ha against a median of 1,756 ha. It lasted 8 days, against 8 days.

In 5 of 17, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.3 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

—first rain
—no rain in ten days
40km/h · max. gust

It was considered over on 28 Feb, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 12 of 17, with a median of 2.3 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 14 Feb 2023
After · 7 Mar 2023

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 24 February 2023 the air beside the fire reached 51 µg/m³ of PM2.5. That day averaged 33: 2.2 times the WHO daily guideline (15).

PM2.5 peak51 µg/m³
Days over the guideline7 days
PM1073 µg/m³
Optical depth0.59
19 Feb21 Feb23 Feb25 Feb
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 · 34Every 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 Wong fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 21 February 2023 to 28 February 2023 (8 days). The perimeter dates it from 21 February 2023 to 23 February 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,059 hectares (10.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Mae Wong (1,064 ha, 1.1 %); Pang Sila Thong (2 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 32.8 °C, humidity dropped to 41 % and gusts hit 40 km/h. The fire danger index (FWI) reached 20, class Moderate.
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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 17. Their median duration was 8 days and their median area 1,756 ha; 100 % went past 1,000 ha. In 5 of 17, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.3 mm.

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: 23 February 2023 → 28 February 2023.

RSS Changes to this page With cross-checks and a citable version

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.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 21 February 2023 to 23 February 2023. 34 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.