Calgary was on track for its least-smoky summer in years, but not anymore
With more wildfire smoke likely on the way for Calgary as we head into the weekend, what might have been a relatively smoke-free summer could soon be called as anything but
After leaving Calgary, Alta., in the clear for most of the summer, heavy wildfire smoke has arrived to cast a familiar orange tint over the city.
And, with more smoke likely on the way as we head into the weekend, what might have been a relatively smoke-free summer could soon be called as anything but.
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Between the start of the year and Sept. 2, just 52 “smoke hours” had been recorded by Environment and Climate Change Canada (ECCC) at the Calgary International Airport.
That left a bit of wiggle room for the city to finish the wildfire season having recorded the fewest smoke hours since 2016, when just one was registered. (69 were recorded in 2019, according to City of Calgary data).
But, after a smoke plume blanketed the city all day Tuesday and Wednesday, and with another likely to pass through the region starting Thursday, 2025’s reputation of bringing a wet, but largely clear summer in Calgary may be in jeopardy.
Smoke obscures the Calgary skyline on the evening of Sept. 2, 2025. (Connor O’Donovan/The Weather Network)
A quick reminder. ECCC defines smoke hours as an hour in which visibility is equal to six statute miles, or 9.7 km or less, due to smoke, as measured by observers at weather stations under 24-7 monitoring, such as at international airports.
“Primarily from the north we’re going to see a plume moving down from the Northwest Territories that’s supposed to track all the way through Alberta right down to Calgary,” says Janelle Gergeley, ECCC operational meteorologist.
“It looks like the weather pattern’s supposed to change into the weekend, so we’re expecting smoke to be around for sure until then. As long as there’s a northwesterly flow, smoke will probably stick around," said Gergeley.
The smoke helped put Calgary air quality into the very high risk category at times Tuesday, with the city’s Air Quality Health Index AQHI rating reading 10+ early in the day, though air quality has since improved. While those with underlying health conditions, seniors, infants and pregnant women are most at risk from wildfire smoke, so ECCC recommends everyone take precautions.
CRAZ air quality program manager Mandeep Dhaliwal says data from the CRAZ network of pollutant sensors confirms a much less smoky year in 2025 than 2024 so far. (Connor O'Donovan/The Weather Network)
The average number of smoke hours in a year in Calgary is 73 (since 1990), although that number is on the rise after several intense wildfire seasons over the past decade.
Most of Canada’s intense wildfire activity this year, however, has remained east of Alberta in provinces including Manitoba and Saskatchewan, which are downwind of prevailing wind patterns relative to Alberta. However, intensifying fire activity in the Northwest Territories, and shifting winds have brought several plumes of smoke to the south.
While smoke hours are based purely on visibility, Calgary’s air quality sensors offer another look into what has been a relatively safer summer for the lungs of city residents.
The Calgary Region Airshed Zone (CRAZ) operates several air quality stations in and around Calgary, measuring pollutants like the hazardous particulate matter, ozone and nitrogen dioxide.
“This year, so far, we’ve had better air quality compared to last year, when we were impacted a lot by forest fires,” said Mandeep Dhaliwal, CRAZ air quality program manager.
“We can look at exceedances of PM2.5, either 1-hour exceedances or exceedances of daily health criteria. Looking at last year and this year, last year we had more of both than we’ve had this year."
And, with dry and unseasonably warm conditions persisting across parts of Western Canada, intensified wildfire activity could bring more smoke this way over the longer term, as well.
(The Weather Network)
The BC Wildfire Service said that between Aug. 28 and Sept. 1, nearly 6,000 lightning strikes were recorded in the province, creating 119 new fires. While 48 of those had been declared out, there were 163 active wildfires on Thursday, with little relief in the forecast.
A ridge of high pressure parked over British Columbia will reinforce, prolonging the unusually high heat many communities have experienced of late. Lytton, B.C., just saw a historic streak of four consecutive 40°C days.
The average temperature anomaly over the next seven days for the province highlights the long-duration nature of the heat event, with much of the inland Interior valleys averaging more than 10°C above seasonal through Sept. 8.