SmogRank / Episodes / Canada

North-western Canada and United States, 19 to 22 July 2025

For 4 days, from 19 to 22 July 2025, 13 cities in Canada and the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Prince Albert, Saskatchewan, Canada: 204.0 µg/m³ on 21 July, about 14× its usual 14.6. Ended 22 July.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached13in 2 countries
Days419 to 22 July 2025
Worst day22 July8 cities counted
Furthest above usual14×Prince Albert

Day by day

22 July 8 cities at twice their usual or more
Sherwood ParkSt. AlbertRed DeerAirdrieCalgaryColumbia FallsFort SaskatchewanEdmontonEstevanLethbridgeHavreGrand CentreMedicine HatFlin FlonReginaSaskatoonFort McMurraySwift CurrentPrince Albert
16 Jul171819202122232425
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

Fort McMurrayFort McMurray, 16 July: 9.1 µg/m³Fort McMurray, 17 July: 26.4 µg/m³Fort McMurray, 18 July: 56.2 µg/m³Fort McMurray, 19 July: 156.0 µg/m³, 8.6× its usual 18.1Fort McMurray, 20 July: 69.0 µg/m³, 3.8× its usual 18.1Fort McMurray, 21 July: 4.3 µg/m³Fort McMurray, 22 July: 3.0 µg/m³Fort McMurray, 23 July: 9.7 µg/m³Fort McMurray, 24 July: 13.4 µg/m³Fort McMurray, 25 July: 11.9 µg/m³Flin FlonFlin Flon, 16 July: no readingFlin Flon, 17 July: 103.0 µg/m³Flin Flon, 18 July: 61.3 µg/m³Flin Flon, 19 July: 104.0 µg/m³, 6.2× its usual 16.9Flin Flon, 20 July: 78.0 µg/m³, 4.3× its usual 18.1Flin Flon, 21 July: 59.3 µg/m³, 3.2× its usual 18.7Flin Flon, 22 July: no readingFlin Flon, 23 July: 49.9 µg/m³Flin Flon, 24 July: 157.0 µg/m³Flin Flon, 25 July: 19.2 µg/m³Prince AlbertPrince Albert, 16 July: 64.0 µg/m³Prince Albert, 17 July: 32.4 µg/m³Prince Albert, 18 July: 28.0 µg/m³Prince Albert, 19 July: 60.6 µg/m³, 4.2× its usual 14.5Prince Albert, 20 July: 47.2 µg/m³, 3.2× its usual 14.6Prince Albert, 21 July: 204.0 µg/m³, 14× its usual 14.6Prince Albert, 22 July: 106.0 µg/m³, 6.8× its usual 15.6Prince Albert, 23 July: 26.6 µg/m³Prince Albert, 24 July: 21.4 µg/m³Prince Albert, 25 July: 11.4 µg/m³Grand CentreGrand Centre, 16 July: 24.9 µg/m³Grand Centre, 17 July: 36.5 µg/m³Grand Centre, 18 July: 57.3 µg/m³Grand Centre, 19 July: 54.1 µg/m³, 4.3× its usual 12.5Grand Centre, 20 July: 40.1 µg/m³, 3.4× its usual 11.9Grand Centre, 21 July: 25.1 µg/m³, 2.2× its usual 11.2Grand Centre, 22 July: 21.3 µg/m³Grand Centre, 23 July: 8.3 µg/m³Grand Centre, 24 July: 10.9 µg/m³Grand Centre, 25 July: 4.2 µg/m³EdmontonEdmonton, 16 July: 29.1 µg/m³Edmonton, 17 July: 42.5 µg/m³Edmonton, 18 July: 16.0 µg/m³Edmonton, 19 July: 20.0 µg/m³Edmonton, 20 July: 30.3 µg/m³, 2.2× its usual 13.6Edmonton, 21 July: 24.2 µg/m³Edmonton, 22 July: 15.7 µg/m³Edmonton, 23 July: 15.1 µg/m³Edmonton, 24 July: 14.3 µg/m³Edmonton, 25 July: 7.2 µg/m³Fort SaskatchewanFort Saskatchewan, 16 July: no readingFort Saskatchewan, 17 July: 34.0 µg/m³Fort Saskatchewan, 18 July: 13.8 µg/m³Fort Saskatchewan, 19 July: 17.3 µg/m³Fort Saskatchewan, 20 July: 25.7 µg/m³, 2.1× its usual 12.4Fort Saskatchewan, 21 July: 22.5 µg/m³Fort Saskatchewan, 22 July: 12.6 µg/m³Fort Saskatchewan, 23 July: 12.4 µg/m³Fort Saskatchewan, 24 July: 11.6 µg/m³Fort Saskatchewan, 25 July: 5.6 µg/m³SaskatoonSaskatoon, 16 July: 59.9 µg/m³Saskatoon, 17 July: 21.6 µg/m³Saskatoon, 18 July: 18.6 µg/m³Saskatoon, 19 July: 21.8 µg/m³Saskatoon, 20 July: 26.6 µg/m³Saskatoon, 21 July: 85.5 µg/m³, 6.3× its usual 13.6Saskatoon, 22 July: 108.0 µg/m³, 8.1× its usual 13.4Saskatoon, 23 July: 17.0 µg/m³Saskatoon, 24 July: 21.8 µg/m³Saskatoon, 25 July: 8.2 µg/m³Swift CurrentSwift Current, 16 July: 57.3 µg/m³Swift Current, 17 July: 9.4 µg/m³Swift Current, 18 July: 14.4 µg/m³Swift Current, 19 July: 6.3 µg/m³Swift Current, 20 July: 4.0 µg/m³Swift Current, 21 July: 22.3 µg/m³Swift Current, 22 July: 121.0 µg/m³, 12× its usual 10.4Swift Current, 23 July: 36.3 µg/m³Swift Current, 24 July: 15.9 µg/m³Swift Current, 25 July: 6.9 µg/m³ReginaRegina, 16 July: 23.9 µg/m³Regina, 17 July: 22.6 µg/m³Regina, 18 July: 25.8 µg/m³Regina, 19 July: 14.0 µg/m³Regina, 20 July: 6.7 µg/m³Regina, 21 July: 20.2 µg/m³Regina, 22 July: 97.7 µg/m³, 7.9× its usual 12.3Regina, 23 July: 53.6 µg/m³Regina, 24 July: 32.3 µg/m³Regina, 25 July: 8.3 µg/m³Medicine HatMedicine Hat, 16 July: 40.5 µg/m³Medicine Hat, 17 July: 6.6 µg/m³Medicine Hat, 18 July: 6.4 µg/m³Medicine Hat, 19 July: 5.7 µg/m³Medicine Hat, 20 July: 4.3 µg/m³Medicine Hat, 21 July: 7.6 µg/m³Medicine Hat, 22 July: 45.5 µg/m³, 5.0× its usual 9.1Medicine Hat, 23 July: 24.7 µg/m³Medicine Hat, 24 July: 9.9 µg/m³Medicine Hat, 25 July: 6.4 µg/m³EstevanEstevan, 16 July: 25.1 µg/m³Estevan, 17 July: 30.1 µg/m³Estevan, 18 July: 13.4 µg/m³Estevan, 19 July: 13.3 µg/m³Estevan, 20 July: 7.5 µg/m³Estevan, 21 July: 11.5 µg/m³Estevan, 22 July: 31.1 µg/m³, 2.2× its usual 14.0Estevan, 23 July: 52.0 µg/m³Estevan, 24 July: 48.8 µg/m³Estevan, 25 July: 10.0 µg/m³LethbridgeLethbridge, 16 July: 19.0 µg/m³Lethbridge, 17 July: 6.6 µg/m³Lethbridge, 18 July: 8.2 µg/m³Lethbridge, 19 July: 4.5 µg/m³Lethbridge, 20 July: 3.9 µg/m³Lethbridge, 21 July: 16.1 µg/m³Lethbridge, 22 July: 27.3 µg/m³, 3.0× its usual 9.2Lethbridge, 23 July: 25.4 µg/m³Lethbridge, 24 July: 7.0 µg/m³Lethbridge, 25 July: 5.4 µg/m³HavreHavre, 16 July: 12.4 µg/m³Havre, 17 July: 4.1 µg/m³Havre, 18 July: 3.0 µg/m³Havre, 19 July: 3.5 µg/m³Havre, 20 July: 3.3 µg/m³Havre, 21 July: 4.5 µg/m³Havre, 22 July: 25.9 µg/m³, 3.3× its usual 7.9Havre, 23 July: 13.0 µg/m³Havre, 24 July: 4.1 µg/m³Havre, 25 July: 4.8 µg/m³16 Jul171819202122232425
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, Canada4 204.021 July14.614×
Swift CurrentSaskatchewan, Canada1 121.022 July10.412×
Fort McMurrayAlberta, Canada2 156.019 July18.18.6×
SaskatoonSaskatchewan, Canada2 108.022 July13.48.1×
ReginaSaskatchewan, Canada1 97.722 July12.37.9×
Flin FlonManitoba, Canada3 104.019 July16.96.2×
Medicine HatAlberta, Canada1 45.522 July9.15.0×
Grand CentreAlberta, Canada3 54.119 July12.54.3×
HavreMontana, United States1 25.922 July7.93.3×
LethbridgeAlberta, Canada1 27.322 July9.23.0×
EstevanSaskatchewan, Canada1 31.122 July14.02.2×
EdmontonAlberta, Canada1 30.320 July13.62.2×
Fort SaskatchewanAlberta, Canada1 25.720 July12.42.1×

Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.

Against other episodes in Canada and the United States

Number 101 of 173 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 173.

Use this page

SmogRank, North-western Canada and United States, 19 to 22 July 2025: 13 cities with PM2.5 at twice their usual or more, 19 to 22 July 2025, smogrank.com/episodes/2025-07-19-north-western-canada-and-united-states (accessed 5 October 2026).

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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.