How many of the fires in Canada between 2016 and 2025, and how much of the area they burned, started with extreme FWI, strong wind, very dry air or after 60 days without rain. Based on the weather on each fire’s start day.
Fire Weather Index (FWI) of 50 or more on the start day: the “extreme” and “very extreme” classes of the European EFFIS scale.
From 2016 to 2025, < 1 % of the fires in Canada started with an extreme FWI (50 or more) and burned 1.1 % of the area.
Gusts of 50 km/h or more on the start day (a gale, Beaufort force 7).
From 2016 to 2025, 9.8 % of the fires in Canada started with gusts of 50 km/h or more and burned 15 % of the area.
Minimum relative humidity below 15% on the start day.
From 2016 to 2025, 2.6 % of the fires in Canada started with air humidity below 15% and burned 9.3 % of the area.
At least 60 days in a row without 1 mm of rain before the start day.
Too few fires in this condition to give a reliable figure.
Each figure compares two shares: how many fires started in that condition and how much of the area they burned. If the second is larger, those fires were bigger than the rest. A fire can meet several conditions at once. These are statistics about the past, not a forecast.
This is not an official warning.
Fire danger warnings are issued by the national authority:
WorldFires, “What weather do fires in Canada start in?”, https://worldfires.org/en/country/canada/fire-weather (accessed 9 November 2026). Sources: Copernicus Climate Change Service, ERA5 (Open-Meteo.com, CC BY 4.0), WorldFires (FWI, Van Wagner 1987), CWFIS NBAC, NASA FIRMS (VIIRS).
Sources: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service, ERA5 (Open-Meteo.com, CC BY 4.0) · WorldFires (FWI, Van Wagner 1987) · CWFIS NBAC · NASA FIRMS (VIIRS)