SmogRank / Episodes / United States
Southern United States and Mexico, May 2025
For 6 days, from 15 to 20 May 2025, 16 cities in the United States and Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Ciudad Benito Juárez, Nuevo León, Mexico: 48.9 µg/m³ on 16 May, about 2.5× its usual 19.6. Ended 20 May.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 16 in 2 countries
Days 6 15 to 20 May 2025
Worst day 17 May 11 cities counted
Furthest above usual 3.8× García
Day by day
Play 17 May 11 cities at twice their usual or more
Live Oak Timberwood Park San Marcos Lockhart Austin Wells Branch Belton College Station Mission Bend Missouri City Houston Conroe Port Isabel Pasadena Heroica Matamoros Seabrook Highlands La Porte Baytown Corsicana Galveston Fort Worth River Oaks Jardines de la Silla Saginaw Saltillo Port Arthur Odessa Corpus Christi Mission Monterrey Santa Catarina Windcrest Ciudad General Escobedo Lacy-Lakeview Helotes Cadereyta Jiménez Ciudad Benito Juárez San Antonio Laredo Edinburg Eagle Pass Kaufman García 12 May 13 14 15 16 17 18 19 20 21 22 23 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
Cadereyta Jiménez Cadereyta Jiménez, 12 May: 21.9 µg/m³ Cadereyta Jiménez, 13 May: 27.6 µg/m³ Cadereyta Jiménez, 14 May: 30.7 µg/m³ Cadereyta Jiménez, 15 May: 33.6 µg/m³, 2.1× its usual 15.7 Cadereyta Jiménez, 16 May: 36.2 µg/m³, 2.5× its usual 14.3 Cadereyta Jiménez, 17 May: 26.0 µg/m³ Cadereyta Jiménez, 18 May: 30.6 µg/m³, 2.4× its usual 12.7 Cadereyta Jiménez, 19 May: 27.1 µg/m³, 2.2× its usual 12.6 Cadereyta Jiménez, 20 May: 23.1 µg/m³ Cadereyta Jiménez, 21 May: 30.3 µg/m³ Cadereyta Jiménez, 22 May: 12.9 µg/m³ Cadereyta Jiménez, 23 May: 19.1 µg/m³ García García, 12 May: 16.4 µg/m³ García, 13 May: 21.9 µg/m³ García, 14 May: 29.2 µg/m³ García, 15 May: 33.1 µg/m³, 2.3× its usual 14.1 García, 16 May: no reading García, 17 May: 48.6 µg/m³, 3.8× its usual 12.9 García, 18 May: no reading García, 19 May: 35.2 µg/m³, 2.9× its usual 12.3 García, 20 May: no reading García, 21 May: no reading García, 22 May: no reading García, 23 May: no reading Ciudad General Esco… Ciudad General Escobedo, 12 May: 16.6 µg/m³ Ciudad General Escobedo, 13 May: 20.9 µg/m³ Ciudad General Escobedo, 14 May: 26.1 µg/m³ Ciudad General Escobedo, 15 May: 30.9 µg/m³, 2.0× its usual 15.2 Ciudad General Escobedo, 16 May: 32.3 µg/m³, 2.2× its usual 14.6 Ciudad General Escobedo, 17 May: 33.1 µg/m³, 2.3× its usual 14.4 Ciudad General Escobedo, 18 May: 33.0 µg/m³, 2.3× its usual 14.2 Ciudad General Escobedo, 19 May: 26.9 µg/m³ Ciudad General Escobedo, 20 May: 26.9 µg/m³ Ciudad General Escobedo, 21 May: 25.5 µg/m³ Ciudad General Escobedo, 22 May: 12.1 µg/m³ Ciudad General Escobedo, 23 May: 19.0 µg/m³ Laredo Laredo, 12 May: 6.7 µg/m³ Laredo, 13 May: 9.5 µg/m³ Laredo, 14 May: 17.0 µg/m³ Laredo, 15 May: 28.0 µg/m³, 2.2× its usual 12.6 Laredo, 16 May: 29.5 µg/m³, 2.4× its usual 12.5 Laredo, 17 May: 32.9 µg/m³, 2.6× its usual 12.5 Laredo, 18 May: 26.3 µg/m³, 2.1× its usual 12.3 Laredo, 19 May: 29.1 µg/m³, 2.4× its usual 12.3 Laredo, 20 May: 30.8 µg/m³, 2.5× its usual 12.1 Laredo, 21 May: 26.5 µg/m³ Laredo, 22 May: 16.6 µg/m³ Laredo, 23 May: 15.0 µg/m³ Ciudad Benito Juárez Ciudad Benito Juárez, 12 May: 24.3 µg/m³ Ciudad Benito Juárez, 13 May: 23.7 µg/m³ Ciudad Benito Juárez, 14 May: 30.3 µg/m³ Ciudad Benito Juárez, 15 May: 39.7 µg/m³ Ciudad Benito Juárez, 16 May: 48.9 µg/m³, 2.5× its usual 19.6 Ciudad Benito Juárez, 17 May: 42.2 µg/m³, 2.3× its usual 18.4 Ciudad Benito Juárez, 18 May: 38.6 µg/m³, 2.2× its usual 17.5 Ciudad Benito Juárez, 19 May: 34.8 µg/m³, 2.0× its usual 17.1 Ciudad Benito Juárez, 20 May: 32.7 µg/m³ Ciudad Benito Juárez, 21 May: 30.0 µg/m³ Ciudad Benito Juárez, 22 May: no reading Ciudad Benito Juárez, 23 May: 24.9 µg/m³ Monterrey Monterrey, 12 May: 15.3 µg/m³ Monterrey, 13 May: 21.5 µg/m³ Monterrey, 14 May: 30.6 µg/m³ Monterrey, 15 May: 34.2 µg/m³ Monterrey, 16 May: 39.2 µg/m³, 2.0× its usual 19.6 Monterrey, 17 May: 37.3 µg/m³, 2.0× its usual 18.6 Monterrey, 18 May: 37.1 µg/m³, 2.1× its usual 17.7 Monterrey, 19 May: 29.1 µg/m³ Monterrey, 20 May: 30.8 µg/m³ Monterrey, 21 May: 30.8 µg/m³ Monterrey, 22 May: 18.3 µg/m³ Monterrey, 23 May: 22.7 µg/m³ Helotes Helotes, 12 May: 6.3 µg/m³ Helotes, 13 May: 9.9 µg/m³ Helotes, 14 May: 14.3 µg/m³ Helotes, 15 May: 21.8 µg/m³ Helotes, 16 May: 27.4 µg/m³, 2.2× its usual 12.3 Helotes, 17 May: 29.1 µg/m³, 2.5× its usual 11.6 Helotes, 18 May: 15.5 µg/m³ Helotes, 19 May: 23.0 µg/m³ Helotes, 20 May: 13.9 µg/m³ Helotes, 21 May: 11.1 µg/m³ Helotes, 22 May: 15.8 µg/m³ Helotes, 23 May: 10.5 µg/m³ Kaufman Kaufman, 12 May: 4.8 µg/m³ Kaufman, 13 May: 9.0 µg/m³ Kaufman, 14 May: 11.1 µg/m³ Kaufman, 15 May: 21.7 µg/m³ Kaufman, 16 May: 26.0 µg/m³, 3.4× its usual 7.7 Kaufman, 17 May: 18.6 µg/m³ Kaufman, 18 May: 13.5 µg/m³ Kaufman, 19 May: 11.7 µg/m³ Kaufman, 20 May: 7.9 µg/m³ Kaufman, 21 May: 5.2 µg/m³ Kaufman, 22 May: 13.8 µg/m³ Kaufman, 23 May: 10.9 µg/m³ San Antonio San Antonio, 12 May: 6.7 µg/m³ San Antonio, 13 May: 9.5 µg/m³ San Antonio, 14 May: 15.3 µg/m³ San Antonio, 15 May: 21.4 µg/m³ San Antonio, 16 May: 25.9 µg/m³, 2.4× its usual 10.7 San Antonio, 17 May: 27.9 µg/m³, 2.6× its usual 10.7 San Antonio, 18 May: 14.6 µg/m³ San Antonio, 19 May: 23.2 µg/m³ San Antonio, 20 May: 15.8 µg/m³ San Antonio, 21 May: 11.3 µg/m³ San Antonio, 22 May: 14.9 µg/m³ San Antonio, 23 May: 10.3 µg/m³ Lacy-Lakeview Lacy-Lakeview, 12 May: 7.0 µg/m³ Lacy-Lakeview, 13 May: 13.9 µg/m³ Lacy-Lakeview, 14 May: 13.5 µg/m³ Lacy-Lakeview, 15 May: 24.1 µg/m³ Lacy-Lakeview, 16 May: 25.1 µg/m³, 2.5× its usual 10.0 Lacy-Lakeview, 17 May: 19.5 µg/m³ Lacy-Lakeview, 18 May: 12.1 µg/m³ Lacy-Lakeview, 19 May: 15.4 µg/m³ Lacy-Lakeview, 20 May: 11.5 µg/m³ Lacy-Lakeview, 21 May: 5.9 µg/m³ Lacy-Lakeview, 22 May: 17.2 µg/m³ Lacy-Lakeview, 23 May: 11.9 µg/m³ Santa Catarina Santa Catarina, 12 May: 17.1 µg/m³ Santa Catarina, 13 May: no reading Santa Catarina, 14 May: no reading Santa Catarina, 15 May: 33.2 µg/m³ Santa Catarina, 16 May: 34.2 µg/m³ Santa Catarina, 17 May: 37.2 µg/m³, 2.2× its usual 16.8 Santa Catarina, 18 May: 34.3 µg/m³, 2.1× its usual 16.0 Santa Catarina, 19 May: 33.3 µg/m³, 2.1× its usual 15.9 Santa Catarina, 20 May: 23.3 µg/m³ Santa Catarina, 21 May: 28.7 µg/m³ Santa Catarina, 22 May: no reading Santa Catarina, 23 May: 17.6 µg/m³ Edinburg Edinburg, 12 May: 11.0 µg/m³ Edinburg, 13 May: 8.4 µg/m³ Edinburg, 14 May: 17.6 µg/m³ Edinburg, 15 May: 16.8 µg/m³ Edinburg, 16 May: 26.8 µg/m³ Edinburg, 17 May: 29.7 µg/m³, 2.0× its usual 14.7 Edinburg, 18 May: 18.9 µg/m³ Edinburg, 19 May: 29.4 µg/m³, 2.1× its usual 13.9 Edinburg, 20 May: 33.4 µg/m³, 2.6× its usual 13.0 Edinburg, 21 May: 19.4 µg/m³ Edinburg, 22 May: 14.3 µg/m³ Edinburg, 23 May: 11.6 µg/m³ Eagle Pass Eagle Pass, 12 May: 4.9 µg/m³ Eagle Pass, 13 May: 9.1 µg/m³ Eagle Pass, 14 May: 13.3 µg/m³ Eagle Pass, 15 May: 23.2 µg/m³ Eagle Pass, 16 May: 24.5 µg/m³ Eagle Pass, 17 May: 29.1 µg/m³, 2.8× its usual 10.5 Eagle Pass, 18 May: 29.8 µg/m³, 2.8× its usual 10.5 Eagle Pass, 19 May: 23.0 µg/m³ Eagle Pass, 20 May: 11.1 µg/m³ Eagle Pass, 21 May: 14.5 µg/m³ Eagle Pass, 22 May: 17.3 µg/m³ Eagle Pass, 23 May: 12.8 µg/m³ Windcrest Windcrest, 12 May: 7.5 µg/m³ Windcrest, 13 May: 10.1 µg/m³ Windcrest, 14 May: 13.0 µg/m³ Windcrest, 15 May: 20.5 µg/m³ Windcrest, 16 May: 24.6 µg/m³ Windcrest, 17 May: 25.4 µg/m³, 2.3× its usual 11.0 Windcrest, 18 May: 13.2 µg/m³ Windcrest, 19 May: 21.8 µg/m³ Windcrest, 20 May: 17.0 µg/m³ Windcrest, 21 May: 10.5 µg/m³ Windcrest, 22 May: 14.5 µg/m³ Windcrest, 23 May: 10.8 µg/m³ Mission Mission, 12 May: 6.2 µg/m³ Mission, 13 May: 8.1 µg/m³ Mission, 14 May: 15.0 µg/m³ Mission, 15 May: 16.9 µg/m³ Mission, 16 May: 25.4 µg/m³ Mission, 17 May: 25.7 µg/m³ Mission, 18 May: 17.9 µg/m³ Mission, 19 May: 26.5 µg/m³ Mission, 20 May: 29.4 µg/m³, 2.0× its usual 14.7 Mission, 21 May: 19.7 µg/m³ Mission, 22 May: 13.5 µg/m³ Mission, 23 May: 12.3 µg/m³ Corpus Christi Corpus Christi, 12 May: 8.0 µg/m³ Corpus Christi, 13 May: 10.0 µg/m³ Corpus Christi, 14 May: 15.4 µg/m³ Corpus Christi, 15 May: 17.5 µg/m³ Corpus Christi, 16 May: 20.5 µg/m³ Corpus Christi, 17 May: 22.2 µg/m³ Corpus Christi, 18 May: 15.5 µg/m³ Corpus Christi, 19 May: 21.5 µg/m³ Corpus Christi, 20 May: 25.4 µg/m³, 2.0× its usual 12.4 Corpus Christi, 21 May: 17.2 µg/m³ Corpus Christi, 22 May: 10.4 µg/m³ Corpus Christi, 23 May: 10.3 µg/m³ 12 May 14 16 18 20 22 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
García Nuevo León, Mexico 3 17 May 12.9 3.8× Kaufman Texas, United States 1 16 May 7.7 3.4× Eagle Pass Texas, United States 2 18 May 10.5 2.8× Edinburg Texas, United States 3 20 May 13.0 2.6× Laredo Texas, United States 6 17 May 12.5 2.6× San Antonio Texas, United States 2 17 May 10.7 2.6× Ciudad Benito Juárez Nuevo León, Mexico 4 16 May 19.6 2.5× Cadereyta Jiménez Nuevo León, Mexico 4 16 May 14.3 2.5× Helotes Texas, United States 2 17 May 11.6 2.5× Lacy-Lakeview Texas, United States 1 16 May 10.0 2.5× Ciudad General Escobedo Nuevo León, Mexico 4 17 May 14.4 2.3× Windcrest Texas, United States 1 17 May 11.0 2.3× Santa Catarina Nuevo León, Mexico 3 17 May 16.8 2.2× Monterrey Nuevo León, Mexico 3 16 May 19.6 2.0× Mission Texas, United States 1 20 May 14.7 2.0× Corpus Christi Texas, United States 1 20 May 12.4 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 and Mexico
Number 83 of 163 episodes in the United States and Mexico since our records began, by cities reached.
Eastern United States and Canada, June and July 2023 343 Northern United States and Canada, July 2026 327 United States and Canada, July 2023 322 Eastern United States and Canada, May and June 2023 317 North-eastern United States and Canada, 29 July to 9 August 2025 292 Northern United States and Canada, May and June 2025 247 United States and Canada, June 2023 195 North-western United States and Canada, August 2023 176 North-western United States and Canada, 4 to 22 August 2026 151 Northern United States and Canada, July 2025 139 Northern United States and Canada, June 2025 134 North-western United States and Canada, July and August 2026 118 Southern United States and Mexico, May 2025 16 Bars: cities reached; colour: the level of the episode's highest daily reading. All 163 .
Use this page SmogRank, Southern United States and Mexico, May 2025: 16 cities with PM2.5 at twice their usual or more, 15 to 20 May 2025, smogrank.com/episodes/2025-05-southern-united-states-and-mexico (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.
