SmogRank / Episodes / Canada

North-western Canada, July 2025

For 4 days, from 14 to 17 July 2025, 10 cities in Canada and the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Saskatoon, Saskatchewan, Canada: 116.0 µg/m³ on 14 July, about 9.5× its usual 12.2.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached10in 2 countries
Days414 to 17 July 2025
Worst day15 July6 cities counted
Furthest above usual9.8×Prince Albert

Day by day

15 July 6 cities at twice their usual or more
AirdrieCalgaryReginaCranbrookRed DeerGreat FallsSt. AlbertEdmontonSherwood ParkLethbridgePrince AlbertMedicine HatSaskatoonSwift Current
11 Jul121314151617181920
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

Prince AlbertPrince Albert, 11 July: 185.0 µg/m³, 14× usualPrince Albert, 12 July: 14.5 µg/m³, 1.1× usualPrince Albert, 13 July: 39.7 µg/m³, 3.1× usualPrince Albert, 14 July: 106.0 µg/m³, 8.2× usualPrince Albert, 15 July: 49.8 µg/m³, 3.8× usualPrince Albert, 16 July: 64.0 µg/m³, 4.9× usualPrince Albert, 17 July: 32.4 µg/m³, 2.5× usualPrince Albert, 18 July: 28.0 µg/m³, 2.2× usualPrince Albert, 19 July: 60.6 µg/m³, 4.7× usualPrince Albert, 20 July: 47.2 µg/m³, 3.6× usualSaskatoonSaskatoon, 11 July: 40.9 µg/m³, 3.4× usualSaskatoon, 12 July: 12.4 µg/m³, 1.0× usualSaskatoon, 13 July: 4.1 µg/m³, 0.3× usualSaskatoon, 14 July: 116.0 µg/m³, 9.5× usualSaskatoon, 15 July: 99.2 µg/m³, 8.1× usualSaskatoon, 16 July: 59.9 µg/m³, 4.9× usualSaskatoon, 17 July: 21.6 µg/m³, 1.8× usualSaskatoon, 18 July: 18.6 µg/m³, 1.5× usualSaskatoon, 19 July: 21.8 µg/m³, 1.8× usualSaskatoon, 20 July: 26.6 µg/m³, 2.2× usualMedicine HatMedicine Hat, 11 July: 8.5 µg/m³, 1.1× usualMedicine Hat, 12 July: 6.0 µg/m³, 0.8× usualMedicine Hat, 13 July: 4.1 µg/m³, 0.5× usualMedicine Hat, 14 July: 41.5 µg/m³, 5.3× usualMedicine Hat, 15 July: 67.6 µg/m³, 8.6× usualMedicine Hat, 16 July: 40.5 µg/m³, 5.1× usualMedicine Hat, 17 July: 6.6 µg/m³, 0.8× usualMedicine Hat, 18 July: 6.4 µg/m³, 0.8× usualMedicine Hat, 19 July: 5.7 µg/m³, 0.7× usualMedicine Hat, 20 July: 4.3 µg/m³, 0.5× usualSwift CurrentSwift Current, 11 July: 11.7 µg/m³, 1.3× usualSwift Current, 12 July: 6.1 µg/m³, 0.7× usualSwift Current, 13 July: 3.6 µg/m³, 0.4× usualSwift Current, 14 July: 40.9 µg/m³, 4.7× usualSwift Current, 15 July: 85.4 µg/m³, 9.8× usualSwift Current, 16 July: 57.3 µg/m³, 6.6× usualSwift Current, 17 July: 9.4 µg/m³, 1.1× usualSwift Current, 18 July: 14.4 µg/m³, 1.7× usualSwift Current, 19 July: 6.3 µg/m³, 0.7× usualSwift Current, 20 July: 4.0 µg/m³, 0.5× usualLethbridgeLethbridge, 11 July: 3.6 µg/m³, 0.5× usualLethbridge, 12 July: 4.8 µg/m³, 0.6× usualLethbridge, 13 July: 4.0 µg/m³, 0.5× usualLethbridge, 14 July: 34.0 µg/m³, 4.3× usualLethbridge, 15 July: 26.3 µg/m³, 3.3× usualLethbridge, 16 July: 19.0 µg/m³, 2.4× usualLethbridge, 17 July: 6.6 µg/m³, 0.8× usualLethbridge, 18 July: 8.2 µg/m³, 1.0× usualLethbridge, 19 July: 4.5 µg/m³, 0.6× usualLethbridge, 20 July: 3.9 µg/m³, 0.5× usualGreat FallsGreat Falls, 11 July: 10.8 µg/m³, 0.9× usualGreat Falls, 12 July: 10.0 µg/m³, 0.8× usualGreat Falls, 13 July: 10.5 µg/m³, 0.8× usualGreat Falls, 14 July: 8.5 µg/m³, 0.7× usualGreat Falls, 15 July: 34.4 µg/m³, 2.7× usualGreat Falls, 16 July: 17.7 µg/m³, 1.4× usualGreat Falls, 17 July: 9.1 µg/m³, 0.7× usualGreat Falls, 18 July: 12.2 µg/m³, 1.0× usualGreat Falls, 19 July: 11.3 µg/m³, 0.9× usualGreat Falls, 20 July: 8.6 µg/m³, 0.7× usualEdmontonEdmonton, 11 July: 15.6 µg/m³, 1.2× usualEdmonton, 12 July: 4.1 µg/m³, 0.3× usualEdmonton, 13 July: 4.1 µg/m³, 0.3× usualEdmonton, 14 July: 13.7 µg/m³, 1.1× usualEdmonton, 15 July: 10.9 µg/m³, 0.9× usualEdmonton, 16 July: 29.1 µg/m³, 2.3× usualEdmonton, 17 July: 42.5 µg/m³, 3.4× usualEdmonton, 18 July: 16.0 µg/m³, 1.3× usualEdmonton, 19 July: 20.0 µg/m³, 1.6× usualEdmonton, 20 July: 30.3 µg/m³, 2.4× usualRed DeerRed Deer, 11 July: 9.5 µg/m³, 0.9× usualRed Deer, 12 July: 7.6 µg/m³, 0.7× usualRed Deer, 13 July: 2.8 µg/m³, 0.3× usualRed Deer, 14 July: 8.6 µg/m³, 0.8× usualRed Deer, 15 July: 7.4 µg/m³, 0.7× usualRed Deer, 16 July: 26.4 µg/m³, 2.5× usualRed Deer, 17 July: 27.7 µg/m³, 2.6× usualRed Deer, 18 July: 6.8 µg/m³, 0.6× usualRed Deer, 19 July: 7.3 µg/m³, 0.7× usualRed Deer, 20 July: 9.4 µg/m³, 0.9× usualSherwood ParkSherwood Park, 11 July: no readingSherwood Park, 12 July: no readingSherwood Park, 13 July: no readingSherwood Park, 14 July: no readingSherwood Park, 15 July: no readingSherwood Park, 16 July: no readingSherwood Park, 17 July: 32.2 µg/m³, 3.7× usualSherwood Park, 18 July: 11.3 µg/m³, 1.3× usualSherwood Park, 19 July: 14.1 µg/m³, 1.6× usualSherwood Park, 20 July: 22.8 µg/m³, 2.7× usualSt. AlbertSt. Albert, 11 July: 8.9 µg/m³, 1.0× usualSt. Albert, 12 July: 2.7 µg/m³, 0.3× usualSt. Albert, 13 July: 2.5 µg/m³, 0.3× usualSt. Albert, 14 July: 8.5 µg/m³, 0.9× usualSt. Albert, 15 July: 6.6 µg/m³, 0.7× usualSt. Albert, 16 July: 21.3 µg/m³, 2.4× usualSt. Albert, 17 July: 28.6 µg/m³, 3.2× usualSt. Albert, 18 July: 12.1 µg/m³, 1.3× usualSt. Albert, 19 July: 13.7 µg/m³, 1.5× usualSt. Albert, 20 July: 19.6 µg/m³, 2.2× usual11 Jul121314151617181920
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
Prince AlbertSaskatchewan, Canada3 185.011 July13.014×
Swift CurrentSaskatchewan, Canada3 85.415 July8.79.8×
SaskatoonSaskatchewan, Canada3 116.014 July12.29.5×
Medicine HatAlberta, Canada3 67.615 July7.98.6×
LethbridgeAlberta, Canada2 34.014 July8.04.3×
Sherwood ParkAlberta, Canada1 32.217 July8.63.7×
EdmontonAlberta, Canada2 42.517 July12.63.4×
St. AlbertAlberta, Canada1 28.617 July9.03.2×
Great FallsMontana, United States1 34.415 July12.62.7×
Red DeerAlberta, Canada2 27.717 July10.62.6×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Against other episodes in Canada and the United States

Number 74 of 106 episodes in Canada and the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 106.

Use this page

SmogRank, North-western Canada, July 2025: 10 cities with PM2.5 at twice their usual or more, 14 to 17 July 2025, smogrank.com/episodes/2025-07-north-western-canada (accessed 2 October 2026).

Download top 10 (PNG)

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.