Rapid Extreme Weather Event Attribution system: top heat events of 2024

Extreme weather event attribution is a climate science approach that explores how events like heat waves, floods, and wildfires are linked to human-caused climate change. By modelling a pre-industrial climate and comparing it to today’s climate, scientists can calculate the influence of human activity on extreme events. Environment and Climate Change Canada’s Rapid Extreme Weather Event Attribution pilot system determines the link between human-caused climate change and heat events across Canada, shortly after they occur. These insights aim to enhance response planning, decision-making, and public understanding of climate impacts.

The map below highlights observed heat events in 2024 that had the largest departures from normal1 in each of the attribution system’s 17 study areas. The statement of likelihood, denoted by the map’s colours, describes whether the heat event was made more or less likely due to human influence on the climate. The probability range quantifies the likelihood statements, with “much more likely,” for example, meaning an event is at least 2x to 10x more likely to occur today compared to a pre-industrial climate. As the map demonstrates, climate change had an impact on extreme heat events across Canada in 2024.

Click here to download a full-resolution version of this graphic as a PDF

Each extreme heat event is described in more detail in the following table. In addition to a statement of likelihood for the current climate, the table below also contains a statement of likelihood for a modelled, future climate.2

Region Date of peak temperature Dates of heatwave duration Peak daily high temperature (°C) Degrees above normal daily high temperature (°C) Normal daily high temperature (°C) Current likelihood
(compared to 1850-1900 base period)
Future likelihood
(SSP2-4.5, 2081-2100 compared to 1850-1900 base period)
Inuvik 09-Aug August 6 to August 10 26.5 13 13.5 Far more likely Far more likely
Kitikmeot 09-Aug August 7 to August 12 25 12.4 12.6 Far more likely Far more likely
Kivalliq 10-Aug August 8 to August 14 27.1 12.2 14.9 Far more likely Far more likely
S. Quebec 19-Jun June 18 to June 20 29.5 10.7 18.8 Much more likely Far more likely
S. Qukiqtaaluk 23-Sep September 20 to October 16 8.8 10.2 -1.4 Far more likely Far more likely
Alberta 10-Jul July 7 to July 11 31.5 9.8 21.7 Much more likely Far more likely
Ft. Smith 18-Jul July 15 to July 20 28.4 9.2 19.2 Much more likely Far more likely
S. BC 21-Jul July 14 to July 22 29.2 9.2 20 Much more likely Far more likely
Yukon 08-Aug August 5 to August 9 24.1 8.9 15.2 Much more likely Far more likely
Sask 19-Jul July 17 to July 22 30.9 8 22.9 Much more likely Much more likely
N. BC 21-Jul July 17 to July 22 24.2 7.2 17 Much more likely Far more likely
N. Quebec 28-Jul July 28 to July 30 24.2 7 17.2 Much more likely Much more likely
Atl. Canada 29-Jul July 28 to July 31 26.1 6.7 19.4 Much more likely Far more likely
Manitoba 30-Jul July 30 to August 1 28.3 6.4 21.9 More likely Much more likely
W. Ontario 27-Jul July 26 to July 28 27.9 6.1 21.8 More likely Much more likely
N. Qikiqtaaluk 12-Sep September 10 to September 14 0.4 5.8 -5.4 More likely Much more likely
E. Ontario 01-Aug July 31 to August 2 29.2 5.8 23.4 Much more likely Much more likely

For more information

Visit Environment and Climate Change Canada’s Extreme Weather Event Attribution website to learn more. Visit ClimateData.ca to learn more about future climate changes, explore interactive maps, and analyze how extreme heat events become more frequent and severe under a range of emissions scenarios.

1 Here “normal” is defined as the average high temperature over a 31-day period centered on the peak temperature day (15 days before and 15 days after), calculated using 1991–2020 climate data for the region.

2 Here the “future climate” is calculated using an ensemble of CMIP6 GCMs running the SSP2-4.5 emissions scenario over the 2081-2100 time period.