Phu Phiang fire, March 2025 ภูเพียง · Phu Phiang, Mae Charim, Wiang Sa
The fire started on 16 March 2025 in Phu Phiang, Thailand, and satellites saw it burning for 16 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 4,375 hectares from heat detections, spread across 3 municipalities.
It is the 16th largest in Nan Province since 2016 (of 189 with a page). Number 11 in Thailand in 2025, of 176.
The power measured by the satellite is low (8.1 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…
- Burnt area
- 4,375ha
- GWIS perimeter (Copernicus)
- Duration
- 16days
- 16 Mar 2025 – 31 Mar 2025
- Municipalities hit
- 3
- districts
- Started on
- 16 Mar
- 2025
- Heat detections
- 146
- in a single hotspot: 8 MW
- Danger at start
- 32
- High · FWI index
- Average daily power
- 25MW
- detected power per day, on average
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 2 days without rain (1 mm or more) when it started. Rain came after the fire: 6.8 mm on 6 Apr.
This area had burned before
86% of the perimeter overlaps earlier fires recorded since 2016: 898 ha in 2016, 1,130 ha in 2017, 683 ha in 2018, 1,712 ha in 2019, 1,955 ha in 2020, 2,116 ha in 2023, 960 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 3,744 ha that had burned before.
- 881 ha Phu Phiang fire, March 2017 1,386 ha in total; the hectares shown are those it shares with this fire
- 813 ha Phu Phiang fire, March 2020 1,058 ha in total; the hectares shown are those it shares with this fire
- 319 ha Wiang Sa fire, March 2016 4,601 ha in total; the hectares shown are those it shares with this fire
- 100 ha Mae Charim fire, March 2023 1,117 ha in total; the hectares shown are those it shares with this fire
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Bangkok boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
1,999 ha reached on 16 Mar4.5 %
-
Mae Charim แม่จริม1,732 ha reached on 21 Mar1.7 %
-
Wiang Sa เวียงสา667 ha reached on 24 Mar0.3 %
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 2025Inside 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) |
|---|---|---|---|---|---|
| 16 Mar | 35.6 °C | 39 % | 32 km/h | 0.1 mm | High 32 |
| 17 Mar | 33.5 °C | 43 % | 36 km/h | 0.0 mm | High 30 |
| 18 Mar | 30.3 °C | 50 % | 38 km/h | 0.0 mm | High 26 |
| 19 Mar | 23.5 °C | 62 % | 27 km/h | 0.6 mm | Moderate 17 |
| 20 Mar | 29.4 °C | 42 % | 19 km/h | 0.0 mm | Moderate 20 |
| 21 Mar | 31.3 °C | 39 % | 20 km/h | 0.0 mm | High 22 |
| 22 Mar | 33.5 °C | 36 % | 19 km/h | 0.0 mm | High 24 |
| 23 Mar | 35.4 °C | 31 % | 22 km/h | 0.0 mm | High 28 |
| 24 Mar | 37.1 °C | 27 % | 23 km/h | 0.0 mm | High 31 |
| 25 Mar | 36.8 °C | 32 % | 29 km/h | 0.0 mm | High 33 |
| 26 Mar | 37.4 °C | 26 % | 34 km/h | 0.0 mm | High 36 |
| 27 Mar | 37.5 °C | 23 % | 33 km/h | 0.0 mm | Very high 38 |
| 28 Mar | 38.0 °C | 26 % | 26 km/h | 0.0 mm | High 36 |
| 29 Mar | 38.9 °C | 25 % | 28 km/h | 0.0 mm | High 37 |
| 30 Mar | 34.5 °C | 43 % | 38 km/h | 0.0 mm | High 34 |
| 31 Mar | 33.5 °C | 48 % | 30 km/h | 0.0 mm | High 27 |
| 1 Apr after | 32.8 °C | 45 % | 31 km/h | 0.0 mm | High 27 |
| 2 Apr after | 33.6 °C | 43 % | 25 km/h | 0.0 mm | High 27 |
| 3 Apr after | 35.3 °C | 39 % | 24 km/h | 0.0 mm | High 27 |
| 4 Apr after | 36.2 °C | 41 % | 30 km/h | 0.0 mm | High 26 |
| 5 Apr after | 34.9 °C | 44 % | 33 km/h | 0.5 mm | High 29 |
| 6 Apr after | 31.1 °C | 60 % | 34 km/h | 6.8 mm | Very low 3 |
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 19 March 2025 the air beside the fire reached 115 µg/m³ of PM2.5. That day averaged 92: 6.1 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 · 146Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 4,601 haWiang Sa เวียงสา31 March 2016 · 20 days · 5 km away
- 15,085 haWiang Sa เวียงสา17 March 2026 · 31 days · 28 km away
- 4,703 haMae Charim แม่จริม27 March 2026 · 22 days · 29 km away
- 6,784 haMueang Nan เมืองน่าน23 March 2023 · 22 days · 36 km away
- 43,391 haNa Noi นาน้อย26 March 2026 · 28 days · 39 km away
Frequently asked questions
- How long did the Phu Phiang fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 16 March 2025 to 31 March 2025 (16 days). The perimeter dates it from 20 March 2025 to 28 March 2025.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 4,375 hectares (43.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 3 municipalities: Phu Phiang (1,999 ha, 4.5 %); Mae Charim (1,732 ha, 1.7 %); Wiang Sa (667 ha, 0.3 %).
- What was the weather like?
- During the fire the temperature reached 38.0 °C, humidity dropped to 23 % and gusts hit 38 km/h. The fire danger index (FWI) reached 38, 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
History of this page Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
No changes since 24 October 2026.
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
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 20 March 2025 to 28 March 2025. 146 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.
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.