SmogRank / Episodes / United States
California, United States, January 2025
For 7 days, from 18 to 24 January 2025, 19 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Oxnard, California, United States: 60.9 µg/m³ on 22 January, about 12× its usual 4.1.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 19 in 1 country
Days 7 18 to 24 January 2025
Worst day 19 January 13 cities counted
Furthest above usual 12× Oxnard
Day by day
Play 19 January 13 cities at twice their usual or more
Clovis Madera Atascadero Nipomo San Luis Obispo Arroyo Grande Orcutt Santa Barbara Goleta Lompoc Santa Clarita Lancaster Simi Valley Ridgecrest Thousand Oaks Merced Agoura La Crescenta-Montrose Burbank Santa Monica Los Angeles Inglewood Turlock Hollister Torrance Glendora Lomita Long Beach Salinas Victorville Prunedale Gilroy Anaheim Seaside Watsonville Fontana Tracy Live Oak Santa Cruz San Jose Lake Elsinore Livermore Sunnyvale Galt Pleasanton South Lake Tahoe Banning Temecula Redwood City Oceanside Carson City Florin Folsom San Leandro Concord Sacramento Roseville Oakland Martinez South San Francisco Berkeley Truckee Davis Lincoln San Francisco Vacaville Vallejo Reno Woodland Poway Spanish Springs San Rafael Indio San Diego El Cajon Chula Vista Summerlin South Tijuana Enterprise Spring Valley Santa Rosa Las Vegas Windsor Henderson Boulder City Brawley El Centro Calexico Ukiah Yuma Compton Bakersfield Imperial Beach Hawthorne Fresno Visalia Modesto Carson Stockton Hanford Porterville Arden-Arcade Jurupa Valley Riverside Corcoran Manteca Yuba City Fillmore Oxnard 15 Jan 16 17 18 19 20 21 22 23 24 25 26 27 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
Visalia Visalia, 15 January: 15.5 µg/m³ Visalia, 16 January: 15.0 µg/m³ Visalia, 17 January: 21.2 µg/m³ Visalia, 18 January: 33.8 µg/m³, 2.5× its usual 13.5 Visalia, 19 January: 32.0 µg/m³, 2.3× its usual 13.8 Visalia, 20 January: 32.5 µg/m³, 2.3× its usual 13.9 Visalia, 21 January: 26.5 µg/m³ Visalia, 22 January: 27.3 µg/m³, 2.1× its usual 12.8 Visalia, 23 January: 30.9 µg/m³, 2.4× its usual 12.7 Visalia, 24 January: 17.9 µg/m³ Visalia, 25 January: 13.1 µg/m³ Visalia, 26 January: 5.5 µg/m³ Visalia, 27 January: 9.8 µg/m³ Fresno Fresno, 15 January: 24.9 µg/m³ Fresno, 16 January: 26.9 µg/m³ Fresno, 17 January: 22.4 µg/m³ Fresno, 18 January: 33.5 µg/m³, 2.4× its usual 14.0 Fresno, 19 January: 30.8 µg/m³, 2.2× its usual 14.0 Fresno, 20 January: 32.0 µg/m³, 2.3× its usual 14.1 Fresno, 21 January: 30.0 µg/m³, 2.1× its usual 14.0 Fresno, 22 January: 28.2 µg/m³, 2.0× its usual 13.9 Fresno, 23 January: 31.3 µg/m³, 2.3× its usual 13.9 Fresno, 24 January: 25.7 µg/m³ Fresno, 25 January: 21.3 µg/m³ Fresno, 26 January: 4.8 µg/m³ Fresno, 27 January: 12.0 µg/m³ Yuba City Yuba City, 15 January: 17.9 µg/m³ Yuba City, 16 January: 15.2 µg/m³ Yuba City, 17 January: 23.8 µg/m³ Yuba City, 18 January: 26.3 µg/m³, 4.0× its usual 6.5 Yuba City, 19 January: 25.8 µg/m³, 3.9× its usual 6.6 Yuba City, 20 January: 4.3 µg/m³ Yuba City, 21 January: 11.5 µg/m³ Yuba City, 22 January: 16.6 µg/m³ Yuba City, 23 January: 20.1 µg/m³ Yuba City, 24 January: 21.9 µg/m³ Yuba City, 25 January: 7.8 µg/m³ Yuba City, 26 January: 3.6 µg/m³ Yuba City, 27 January: 3.8 µg/m³ Corcoran Corcoran, 15 January: 18.2 µg/m³ Corcoran, 16 January: 20.3 µg/m³ Corcoran, 17 January: 21.7 µg/m³ Corcoran, 18 January: 25.3 µg/m³, 2.1× its usual 11.8 Corcoran, 19 January: 28.6 µg/m³, 2.4× its usual 12.0 Corcoran, 20 January: 22.5 µg/m³ Corcoran, 21 January: 26.9 µg/m³, 2.2× its usual 12.1 Corcoran, 22 January: 24.0 µg/m³ Corcoran, 23 January: 36.4 µg/m³, 3.3× its usual 11.1 Corcoran, 24 January: 30.6 µg/m³, 2.8× its usual 11.0 Corcoran, 25 January: 14.5 µg/m³ Corcoran, 26 January: 6.6 µg/m³ Corcoran, 27 January: 4.8 µg/m³ Imperial Beach Imperial Beach, 15 January: 11.0 µg/m³ Imperial Beach, 16 January: 20.5 µg/m³ Imperial Beach, 17 January: 24.8 µg/m³ Imperial Beach, 18 January: 23.7 µg/m³ Imperial Beach, 19 January: 34.8 µg/m³, 2.3× its usual 15.1 Imperial Beach, 20 January: 12.3 µg/m³ Imperial Beach, 21 January: 12.3 µg/m³ Imperial Beach, 22 January: 13.4 µg/m³ Imperial Beach, 23 January: 15.0 µg/m³ Imperial Beach, 24 January: 18.8 µg/m³ Imperial Beach, 25 January: 44.4 µg/m³ Imperial Beach, 26 January: 6.9 µg/m³ Imperial Beach, 27 January: 6.8 µg/m³ Hanford Hanford, 15 January: 25.8 µg/m³ Hanford, 16 January: 27.9 µg/m³ Hanford, 17 January: 27.3 µg/m³ Hanford, 18 January: 25.6 µg/m³ Hanford, 19 January: 33.5 µg/m³, 2.5× its usual 13.6 Hanford, 20 January: 28.1 µg/m³, 2.0× its usual 13.8 Hanford, 21 January: 29.9 µg/m³, 2.2× its usual 13.7 Hanford, 22 January: 28.8 µg/m³, 2.2× its usual 13.2 Hanford, 23 January: 37.0 µg/m³, 2.8× its usual 13.2 Hanford, 24 January: 34.8 µg/m³, 2.6× its usual 13.2 Hanford, 25 January: 22.3 µg/m³ Hanford, 26 January: 6.5 µg/m³ Hanford, 27 January: 8.3 µg/m³ Bakersfield Bakersfield, 15 January: 17.0 µg/m³ Bakersfield, 16 January: 13.7 µg/m³ Bakersfield, 17 January: 18.1 µg/m³ Bakersfield, 18 January: 26.1 µg/m³ Bakersfield, 19 January: 31.6 µg/m³, 2.3× its usual 13.8 Bakersfield, 20 January: 32.9 µg/m³, 2.2× its usual 14.9 Bakersfield, 21 January: 28.3 µg/m³, 2.0× its usual 14.1 Bakersfield, 22 January: 28.2 µg/m³, 2.1× its usual 13.5 Bakersfield, 23 January: 26.8 µg/m³, 2.0× its usual 13.4 Bakersfield, 24 January: 24.5 µg/m³ Bakersfield, 25 January: 12.4 µg/m³ Bakersfield, 26 January: 7.6 µg/m³ Bakersfield, 27 January: 6.8 µg/m³ Jurupa Valley Jurupa Valley, 15 January: 3.4 µg/m³ Jurupa Valley, 16 January: 9.8 µg/m³ Jurupa Valley, 17 January: 13.8 µg/m³ Jurupa Valley, 18 January: 20.2 µg/m³ Jurupa Valley, 19 January: 31.5 µg/m³, 3.0× its usual 10.6 Jurupa Valley, 20 January: 15.3 µg/m³ Jurupa Valley, 21 January: 5.6 µg/m³ Jurupa Valley, 22 January: 6.5 µg/m³ Jurupa Valley, 23 January: 2.7 µg/m³ Jurupa Valley, 24 January: 7.7 µg/m³ Jurupa Valley, 25 January: 15.9 µg/m³ Jurupa Valley, 26 January: 6.8 µg/m³ Jurupa Valley, 27 January: 7.1 µg/m³ Riverside Riverside, 15 January: 6.0 µg/m³ Riverside, 16 January: 6.1 µg/m³ Riverside, 17 January: 11.2 µg/m³ Riverside, 18 January: 17.9 µg/m³ Riverside, 19 January: 28.4 µg/m³, 3.2× its usual 8.8 Riverside, 20 January: 15.4 µg/m³ Riverside, 21 January: 3.7 µg/m³ Riverside, 22 January: 5.7 µg/m³ Riverside, 23 January: 3.2 µg/m³ Riverside, 24 January: 5.8 µg/m³ Riverside, 25 January: 12.1 µg/m³ Riverside, 26 January: 4.2 µg/m³ Riverside, 27 January: 4.4 µg/m³ Compton Compton, 15 January: 16.6 µg/m³ Compton, 16 January: 12.0 µg/m³ Compton, 17 January: 12.7 µg/m³ Compton, 18 January: 21.2 µg/m³ Compton, 19 January: 27.7 µg/m³, 2.0× its usual 13.6 Compton, 20 January: 14.4 µg/m³ Compton, 21 January: 14.5 µg/m³ Compton, 22 January: 12.9 µg/m³ Compton, 23 January: 20.1 µg/m³ Compton, 24 January: 9.3 µg/m³ Compton, 25 January: 13.1 µg/m³ Compton, 26 January: 5.1 µg/m³ Compton, 27 January: 6.5 µg/m³ Carson Carson, 15 January: 11.8 µg/m³ Carson, 16 January: 9.1 µg/m³ Carson, 17 January: 11.6 µg/m³ Carson, 18 January: 18.7 µg/m³ Carson, 19 January: 27.4 µg/m³, 2.7× its usual 10.2 Carson, 20 January: 15.1 µg/m³ Carson, 21 January: no reading Carson, 22 January: 9.0 µg/m³ Carson, 23 January: 11.5 µg/m³ Carson, 24 January: 6.7 µg/m³ Carson, 25 January: no reading Carson, 26 January: no reading Carson, 27 January: no reading Porterville Porterville, 15 January: 9.3 µg/m³ Porterville, 16 January: 7.6 µg/m³ Porterville, 17 January: 14.7 µg/m³ Porterville, 18 January: 21.1 µg/m³ Porterville, 19 January: 27.3 µg/m³, 2.8× its usual 9.8 Porterville, 20 January: 28.6 µg/m³, 2.9× its usual 10.0 Porterville, 21 January: 23.0 µg/m³ Porterville, 22 January: 22.6 µg/m³ Porterville, 23 January: 21.5 µg/m³ Porterville, 24 January: 11.1 µg/m³ Porterville, 25 January: 8.7 µg/m³ Porterville, 26 January: 8.2 µg/m³ Porterville, 27 January: 7.2 µg/m³ Hawthorne Hawthorne, 15 January: 13.6 µg/m³ Hawthorne, 16 January: 10.9 µg/m³ Hawthorne, 17 January: 13.5 µg/m³ Hawthorne, 18 January: 20.2 µg/m³ Hawthorne, 19 January: 26.8 µg/m³, 2.4× its usual 11.3 Hawthorne, 20 January: 16.3 µg/m³ Hawthorne, 21 January: no reading Hawthorne, 22 January: 10.1 µg/m³ Hawthorne, 23 January: 13.8 µg/m³ Hawthorne, 24 January: 6.9 µg/m³ Hawthorne, 25 January: no reading Hawthorne, 26 January: no reading Hawthorne, 27 January: no reading Oxnard Oxnard, 15 January: 1.8 µg/m³ Oxnard, 16 January: 2.8 µg/m³ Oxnard, 17 January: 5.5 µg/m³ Oxnard, 18 January: 7.5 µg/m³ Oxnard, 19 January: 7.6 µg/m³ Oxnard, 20 January: 8.7 µg/m³ Oxnard, 21 January: 2.3 µg/m³ Oxnard, 22 January: 60.9 µg/m³, 12× its usual 4.1 Oxnard, 23 January: 5.6 µg/m³ Oxnard, 24 January: 3.2 µg/m³ Oxnard, 25 January: 5.4 µg/m³ Oxnard, 26 January: 3.3 µg/m³ Oxnard, 27 January: 2.0 µg/m³ Fillmore Fillmore, 15 January: no reading Fillmore, 16 January: 3.1 µg/m³ Fillmore, 17 January: no reading Fillmore, 18 January: no reading Fillmore, 19 January: no reading Fillmore, 20 January: no reading Fillmore, 21 January: 2.4 µg/m³ Fillmore, 22 January: 52.2 µg/m³, 10× its usual 2.7 Fillmore, 23 January: no reading Fillmore, 24 January: no reading Fillmore, 25 January: 6.5 µg/m³ Fillmore, 26 January: 2.8 µg/m³ Fillmore, 27 January: 2.3 µg/m³ Stockton Stockton, 15 January: no reading Stockton, 16 January: no reading Stockton, 17 January: no reading Stockton, 18 January: 20.0 µg/m³ Stockton, 19 January: 23.8 µg/m³ Stockton, 20 January: 13.1 µg/m³ Stockton, 21 January: 21.2 µg/m³ Stockton, 22 January: 23.3 µg/m³ Stockton, 23 January: 29.2 µg/m³, 2.7× its usual 11.0 Stockton, 24 January: 27.5 µg/m³, 2.6× its usual 10.7 Stockton, 25 January: 21.7 µg/m³ Stockton, 26 January: 6.0 µg/m³ Stockton, 27 January: 8.7 µg/m³ Manteca Manteca, 15 January: 23.0 µg/m³ Manteca, 16 January: 20.6 µg/m³ Manteca, 17 January: 18.8 µg/m³ Manteca, 18 January: 14.0 µg/m³ Manteca, 19 January: 24.1 µg/m³ Manteca, 20 January: 9.0 µg/m³ Manteca, 21 January: 17.0 µg/m³ Manteca, 22 January: 16.1 µg/m³ Manteca, 23 January: 23.5 µg/m³ Manteca, 24 January: 29.5 µg/m³, 3.6× its usual 8.3 Manteca, 25 January: 16.5 µg/m³ Manteca, 26 January: 7.5 µg/m³ Manteca, 27 January: 7.9 µg/m³ Modesto Modesto, 15 January: 18.3 µg/m³ Modesto, 16 January: 21.6 µg/m³ Modesto, 17 January: 20.8 µg/m³ Modesto, 18 January: 17.2 µg/m³ Modesto, 19 January: 23.0 µg/m³ Modesto, 20 January: 12.7 µg/m³ Modesto, 21 January: 16.4 µg/m³ Modesto, 22 January: 19.0 µg/m³ Modesto, 23 January: 24.3 µg/m³ Modesto, 24 January: 27.8 µg/m³, 2.6× its usual 10.9 Modesto, 25 January: 14.3 µg/m³ Modesto, 26 January: 5.6 µg/m³ Modesto, 27 January: 7.6 µg/m³ Arden-Arcade Arden-Arcade, 15 January: 17.4 µg/m³ Arden-Arcade, 16 January: 15.1 µg/m³ Arden-Arcade, 17 January: 18.3 µg/m³ Arden-Arcade, 18 January: 22.0 µg/m³ Arden-Arcade, 19 January: 24.2 µg/m³ Arden-Arcade, 20 January: 15.8 µg/m³ Arden-Arcade, 21 January: 12.5 µg/m³ Arden-Arcade, 22 January: 16.6 µg/m³ Arden-Arcade, 23 January: 20.7 µg/m³ Arden-Arcade, 24 January: 25.0 µg/m³, 3.0× its usual 8.3 Arden-Arcade, 25 January: 19.1 µg/m³ Arden-Arcade, 26 January: 8.0 µg/m³ Arden-Arcade, 27 January: 7.4 µg/m³ 15 Jan 17 19 21 23 25 27 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. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Oxnard California, United States 1 22 January 4.1 12× Fillmore California, United States 1 22 January 2.7 10× Yuba City California, United States 2 18 January 6.5 4.0× Manteca California, United States 1 24 January 8.3 3.6× Corcoran California, United States 5 23 January 11.1 3.3× Riverside California, United States 1 19 January 8.8 3.2× Jurupa Valley California, United States 1 19 January 10.6 3.0× Arden-Arcade California, United States 1 24 January 8.3 3.0× Porterville California, United States 2 20 January 10.0 2.9× Hanford California, United States 6 23 January 13.2 2.8× Stockton California, United States 2 23 January 11.0 2.7× Carson California, United States 1 19 January 10.2 2.7× Modesto California, United States 1 24 January 10.9 2.6× Visalia California, United States 5 18 January 13.5 2.5× Fresno California, United States 6 18 January 14.0 2.4× Hawthorne California, United States 1 19 January 11.3 2.4× Imperial Beach California, United States 1 19 January 15.1 2.3× Bakersfield California, United States 5 20 January 14.9 2.2× Compton California, United States 1 19 January 13.6 2.0×
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 the United States
Number 57 of 130 episodes in the United States since our records began, by cities reached.
Eastern United States and Canada, 25 June to 2 July 2023 280 North-eastern United States and Canada, July 2026 264 Eastern United States and Canada, May and June 2023 261 North-eastern United States and Canada, 30 July to 9 August 2025 241 Eastern United States and Canada, July 2023 240 North-eastern United States and Canada, 3 to 9 June 2025 196 Eastern United States and Canada, 14 to 19 June 2023 161 North-eastern United States and Canada, 12 to 16 July 2025 119 North-western United States and Canada, August 2023 110 North-eastern United States and Canada, 10 to 14 June 2025 104 North-western United States and Canada, 4 to 11 August 2026 99 North-eastern United States and Canada, 14 to 19 February 2026 96 California, United States, January 2025 19 Bars: cities reached; colour: the level of the episode's highest daily reading. All 130 .
Use this page SmogRank, California, United States, January 2025: 19 cities with PM2.5 at twice their usual or more, 18 to 24 January 2025, smogrank.com/episodes/2025-01-california-united-states (accessed 4 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.
