Ako fire, 7 September 2026 Ako
The fire started on 7 September 2026 in Ako, Japan, and satellites saw it burning for 17 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 220 hectares from heat detections, spread across a single municipality.
Number 80 in Japan in 2026, of 94.
The power measured by the satellite is low (2.3 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
- 220ha
- GWIS perimeter (Copernicus)
- Duration
- 17days
- 7 Sept 2026 – 23 Sept 2026
- Municipalities hit
- 1
- municipalities
- Started on
- 7 Sept
- 2026
- Heat detections
- 20
- in a single hotspot: 2 MW
- Danger at start
- 1
- Very low · FWI index
- Energy released
- 24MW
- sum of detected power
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 0 days without rain (1 mm or more) when it started. Rain came after the fire: 22.4 mm on 4 Oct.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
What happened to each town
-
Ako where it started180 ha reached on 7 Sept1.4 %
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) |
|---|---|---|---|---|---|
| 7 Sept | 28.1 °C | 65 % | 16 km/h | 0.4 mm | Very low 1 |
| 8 Sept | 25.8 °C | 72 % | 14 km/h | 20.7 mm | Very low 0 |
| 9 Sept | 26.0 °C | 68 % | 27 km/h | 55.1 mm | Very low 0 |
| 10 Sept | 27.2 °C | 55 % | 22 km/h | 0.0 mm | Very low 0 |
| 11 Sept | 27.0 °C | 66 % | 10 km/h | 0.0 mm | Very low 1 |
| 12 Sept | 28.1 °C | 61 % | 13 km/h | 0.0 mm | Very low 2 |
| 13 Sept | 28.6 °C | 76 % | 23 km/h | 8.9 mm | Very low 0 |
| 14 Sept | 27.0 °C | 85 % | 16 km/h | 44.5 mm | Very low 0 |
| 15 Sept | 25.1 °C | 84 % | 16 km/h | 8.7 mm | Very low 0 |
| 16 Sept | 26.5 °C | 58 % | 26 km/h | 0.4 mm | Very low 0 |
| 17 Sept | 28.4 °C | 52 % | 27 km/h | 0.0 mm | Very low 1 |
| 18 Sept | 28.0 °C | 62 % | 17 km/h | 0.2 mm | Very low 1 |
| 19 Sept | 30.5 °C | 54 % | 17 km/h | 0.0 mm | Very low 3 |
| 20 Sept | 29.8 °C | 55 % | 27 km/h | 0.4 mm | Very low 5 |
| 21 Sept | 28.1 °C | 60 % | 39 km/h | 0.0 mm | Low 7 |
| 22 Sept | 29.0 °C | 44 % | 31 km/h | 0.0 mm | Low 8 |
| 23 Sept | 26.5 °C | 60 % | 12 km/h | 0.0 mm | Very low 5 |
| 24 Sept after | 28.2 °C | 51 % | 21 km/h | 0.0 mm | Low 6 |
| 25 Sept after | 26.8 °C | 53 % | 13 km/h | 0.3 mm | Low 6 |
| 26 Sept after | 24.4 °C | 65 % | 15 km/h | 9.3 mm | Very low 0 |
| 27 Sept after | 23.4 °C | 81 % | 21 km/h | 21.1 mm | Very low 0 |
| 28 Sept after | 24.5 °C | 87 % | 25 km/h | 37.6 mm | Very low 0 |
| 29 Sept after | 22.3 °C | 82 % | 19 km/h | 39.2 mm | Very low 0 |
| 30 Sept after | 25.0 °C | 58 % | 12 km/h | 0.0 mm | Very low 0 |
| 1 Oct after | 27.5 °C | 56 % | 16 km/h | 0.0 mm | Very low 0 |
| 2 Oct after | 26.0 °C | 38 % | 27 km/h | 0.0 mm | Very low 3 |
| 3 Oct after | 24.8 °C | 39 % | 28 km/h | 0.0 mm | Very low 5 |
| 4 Oct after | 20.2 °C | 54 % | 20 km/h | 22.4 mm | Very low 0 |
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 23 September 2026 the air beside the fire reached 26 µg/m³ of PM2.5. That day averaged 19: 1.3 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 · 20Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Ako fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 7 September 2026 to 23 September 2026 (17 days). The perimeter dates it from 12 September 2026 to 16 September 2026.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 220 hectares (2.2 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Ako (180 ha, 1.4 %).
- What was the weather like?
- During the fire the temperature reached 30.5 °C, humidity dropped to 38 % and gusts hit 39 km/h. The fire danger index (FWI) reached 8, class Low.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Japan (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: 119
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
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-ShareAlike 2.0). 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.