SmogRank / Episodes / Mexico
Southern Mexico, January 2026
For 5 days, from 5 to 9 January 2026, 12 cities in Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Aguascalientes, Aguascalientes, Mexico: 128.4 µg/m³ on 6 January, about 4.4× its usual 29.2.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 12 in 1 country
Days 5 5 to 9 January 2026
Worst day 6 January 6 cities counted
Furthest above usual 4.4× Aguascalientes
Day by day
Play 6 January 6 cities at twice their usual or more
Xonacatlán Naucalpan de Juárez Mexico City Celaya Ciudad Nezahualcoyotl San Luis de la Paz Cuernavaca Salamanca Tulancingo Guanajuato Zacatepec de Hidalgo San Martin Texmelucan de Labastida Silao de la Victoria Tlaxcala Apizaco Atlixco Puebla San Luis Potosí Tlaquepaque Guadalajara Hacienda Santa Fe Zapopan Santa Anita Yecapixtla Tula de Allende La Providencia Siglo XXI Tehuacán León de los Aldama San Miguel de Allende Mixquiahuala de Juárez Irapuato San Juan del Río Santiago de Querétaro Abasolo Aguascalientes 2 Jan 3 4 5 6 7 8 9 10 11 12 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
Aguascalientes Aguascalientes, 2 January: 47.9 µg/m³, 1.6× usual Aguascalientes, 3 January: 39.7 µg/m³, 1.4× usual Aguascalientes, 4 January: 114.9 µg/m³, 3.9× usual Aguascalientes, 5 January: 103.5 µg/m³, 3.5× usual Aguascalientes, 6 January: 128.4 µg/m³, 4.4× usual Aguascalientes, 7 January: 57.3 µg/m³, 2.0× usual Aguascalientes, 8 January: 41.6 µg/m³, 1.4× usual Aguascalientes, 9 January: 36.7 µg/m³, 1.3× usual Aguascalientes, 10 January: 43.4 µg/m³, 1.5× usual Aguascalientes, 11 January: 23.7 µg/m³, 0.8× usual Aguascalientes, 12 January: 29.4 µg/m³, 1.0× usual San Juan del Río San Juan del Río, 2 January: 16.3 µg/m³, 1.3× usual San Juan del Río, 3 January: 19.8 µg/m³, 1.6× usual San Juan del Río, 4 January: 14.7 µg/m³, 1.2× usual San Juan del Río, 5 January: 30.7 µg/m³, 2.5× usual San Juan del Río, 6 January: 26.4 µg/m³, 2.1× usual San Juan del Río, 7 January: 25.7 µg/m³, 2.1× usual San Juan del Río, 8 January: 28.2 µg/m³, 2.3× usual San Juan del Río, 9 January: 26.2 µg/m³, 2.1× usual San Juan del Río, 10 January: 20.8 µg/m³, 1.7× usual San Juan del Río, 11 January: 6.1 µg/m³, 0.5× usual San Juan del Río, 12 January: 17.5 µg/m³, 1.4× usual Abasolo Abasolo, 2 January: 27.5 µg/m³, 1.9× usual Abasolo, 3 January: 25.0 µg/m³, 1.7× usual Abasolo, 4 January: 20.1 µg/m³, 1.4× usual Abasolo, 5 January: 29.6 µg/m³, 2.1× usual Abasolo, 6 January: 31.5 µg/m³, 2.2× usual Abasolo, 7 January: 39.8 µg/m³, 2.8× usual Abasolo, 8 January: 25.2 µg/m³, 1.8× usual Abasolo, 9 January: 24.9 µg/m³, 1.7× usual Abasolo, 10 January: 24.7 µg/m³, 1.7× usual Abasolo, 11 January: 9.3 µg/m³, 0.6× usual Abasolo, 12 January: 10.2 µg/m³, 0.7× usual San Miguel de Allen… San Miguel de Allende, 2 January: 21.2 µg/m³, 1.8× usual San Miguel de Allende, 3 January: 20.9 µg/m³, 1.8× usual San Miguel de Allende, 4 January: 15.6 µg/m³, 1.3× usual San Miguel de Allende, 5 January: 25.7 µg/m³, 2.2× usual San Miguel de Allende, 6 January: 27.0 µg/m³, 2.3× usual San Miguel de Allende, 7 January: 26.2 µg/m³, 2.2× usual San Miguel de Allende, 8 January: no reading San Miguel de Allende, 9 January: no reading San Miguel de Allende, 10 January: no reading San Miguel de Allende, 11 January: 7.5 µg/m³, 0.6× usual San Miguel de Allende, 12 January: 9.4 µg/m³, 0.8× usual Santiago de Queréta… Santiago de Querétaro, 2 January: 22.6 µg/m³, 1.5× usual Santiago de Querétaro, 3 January: 26.1 µg/m³, 1.7× usual Santiago de Querétaro, 4 January: 14.2 µg/m³, 0.9× usual Santiago de Querétaro, 5 January: 28.5 µg/m³, 1.9× usual Santiago de Querétaro, 6 January: 42.3 µg/m³, 2.8× usual Santiago de Querétaro, 7 January: 29.8 µg/m³, 2.0× usual Santiago de Querétaro, 8 January: 39.5 µg/m³, 2.6× usual Santiago de Querétaro, 9 January: 32.8 µg/m³, 2.2× usual Santiago de Querétaro, 10 January: 30.3 µg/m³, 2.0× usual Santiago de Querétaro, 11 January: 5.0 µg/m³, 0.3× usual Santiago de Querétaro, 12 January: 8.9 µg/m³, 0.6× usual Yecapixtla Yecapixtla, 2 January: no reading Yecapixtla, 3 January: no reading Yecapixtla, 4 January: no reading Yecapixtla, 5 January: no reading Yecapixtla, 6 January: 29.3 µg/m³, 2.0× usual Yecapixtla, 7 January: 29.3 µg/m³, 2.0× usual Yecapixtla, 8 January: 22.6 µg/m³, 1.6× usual Yecapixtla, 9 January: 33.4 µg/m³, 2.3× usual Yecapixtla, 10 January: 19.3 µg/m³, 1.3× usual Yecapixtla, 11 January: 12.5 µg/m³, 0.9× usual Yecapixtla, 12 January: 6.7 µg/m³, 0.5× usual Irapuato Irapuato, 2 January: 35.6 µg/m³, 1.8× usual Irapuato, 3 January: 29.7 µg/m³, 1.5× usual Irapuato, 4 January: 30.0 µg/m³, 1.5× usual Irapuato, 5 January: 36.2 µg/m³, 1.9× usual Irapuato, 6 January: 37.6 µg/m³, 1.9× usual Irapuato, 7 January: 45.9 µg/m³, 2.4× usual Irapuato, 8 January: no reading Irapuato, 9 January: no reading Irapuato, 10 January: no reading Irapuato, 11 January: 8.7 µg/m³, 0.4× usual Irapuato, 12 January: 14.8 µg/m³, 0.8× usual León de los Aldama León de los Aldama, 2 January: 28.8 µg/m³, 1.7× usual León de los Aldama, 3 January: 29.1 µg/m³, 1.7× usual León de los Aldama, 4 January: 22.0 µg/m³, 1.3× usual León de los Aldama, 5 January: 29.4 µg/m³, 1.7× usual León de los Aldama, 6 January: 32.2 µg/m³, 1.9× usual León de los Aldama, 7 January: 38.3 µg/m³, 2.3× usual León de los Aldama, 8 January: no reading León de los Aldama, 9 January: no reading León de los Aldama, 10 January: no reading León de los Aldama, 11 January: 12.7 µg/m³, 0.7× usual León de los Aldama, 12 January: 15.4 µg/m³, 0.9× usual Mixquiahuala de Juá… Mixquiahuala de Juárez, 2 January: 22.8 µg/m³, 1.2× usual Mixquiahuala de Juárez, 3 January: 27.8 µg/m³, 1.5× usual Mixquiahuala de Juárez, 4 January: 22.8 µg/m³, 1.2× usual Mixquiahuala de Juárez, 5 January: 29.9 µg/m³, 1.6× usual Mixquiahuala de Juárez, 6 January: 34.8 µg/m³, 1.9× usual Mixquiahuala de Juárez, 7 January: 34.4 µg/m³, 1.9× usual Mixquiahuala de Juárez, 8 January: 44.9 µg/m³, 2.4× usual Mixquiahuala de Juárez, 9 January: 44.3 µg/m³, 2.4× usual Mixquiahuala de Juárez, 10 January: 32.4 µg/m³, 1.8× usual Mixquiahuala de Juárez, 11 January: 6.5 µg/m³, 0.4× usual Mixquiahuala de Juárez, 12 January: 10.9 µg/m³, 0.6× usual La Providencia Sigl… La Providencia Siglo XXI, 2 January: 15.3 µg/m³, 0.8× usual La Providencia Siglo XXI, 3 January: 19.9 µg/m³, 1.1× usual La Providencia Siglo XXI, 4 January: 17.0 µg/m³, 0.9× usual La Providencia Siglo XXI, 5 January: 21.8 µg/m³, 1.2× usual La Providencia Siglo XXI, 6 January: 23.2 µg/m³, 1.2× usual La Providencia Siglo XXI, 7 January: 22.6 µg/m³, 1.2× usual La Providencia Siglo XXI, 8 January: 40.9 µg/m³, 2.2× usual La Providencia Siglo XXI, 9 January: 39.6 µg/m³, 2.1× usual La Providencia Siglo XXI, 10 January: 30.9 µg/m³, 1.7× usual La Providencia Siglo XXI, 11 January: 5.6 µg/m³, 0.3× usual La Providencia Siglo XXI, 12 January: 12.1 µg/m³, 0.7× usual Tehuacán Tehuacán, 2 January: 21.0 µg/m³, 1.4× usual Tehuacán, 3 January: 21.5 µg/m³, 1.4× usual Tehuacán, 4 January: 17.7 µg/m³, 1.2× usual Tehuacán, 5 January: 25.3 µg/m³, 1.7× usual Tehuacán, 6 January: 27.3 µg/m³, 1.8× usual Tehuacán, 7 January: 26.0 µg/m³, 1.7× usual Tehuacán, 8 January: 33.4 µg/m³, 2.2× usual Tehuacán, 9 January: 31.9 µg/m³, 2.1× usual Tehuacán, 10 January: 28.3 µg/m³, 1.9× usual Tehuacán, 11 January: 13.9 µg/m³, 0.9× usual Tehuacán, 12 January: 3.8 µg/m³, 0.3× usual Tula de Allende Tula de Allende, 2 January: 18.3 µg/m³, 1.2× usual Tula de Allende, 3 January: 20.3 µg/m³, 1.3× usual Tula de Allende, 4 January: 18.9 µg/m³, 1.2× usual Tula de Allende, 5 January: 24.5 µg/m³, 1.6× usual Tula de Allende, 6 January: 26.1 µg/m³, 1.7× usual Tula de Allende, 7 January: 25.5 µg/m³, 1.7× usual Tula de Allende, 8 January: 31.6 µg/m³, 2.1× usual Tula de Allende, 9 January: 31.9 µg/m³, 2.1× usual Tula de Allende, 10 January: 23.8 µg/m³, 1.6× usual Tula de Allende, 11 January: 6.6 µg/m³, 0.4× usual Tula de Allende, 12 January: 23.4 µg/m³, 1.5× usual 2 Jan 4 6 8 10 12 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
Aguascalientes Aguascalientes, Mexico 2 6 January 29.2 4.4× Santiago de Querétaro Querétaro, Mexico 2 6 January 15.0 2.8× Abasolo Guanajuato, Mexico 3 7 January 14.4 2.8× San Juan del Río Querétaro, Mexico 4 5 January 12.5 2.5× Mixquiahuala de Juárez Hidalgo, Mexico 2 8 January 18.5 2.4× Irapuato Guanajuato, Mexico 1 7 January 19.5 2.4× Yecapixtla Morelos, Mexico 2 9 January 14.5 2.3× San Miguel de Allende Guanajuato, Mexico 3 6 January 11.9 2.3× León de los Aldama Guanajuato, Mexico 1 7 January 17.0 2.3× La Providencia Siglo XXI Hidalgo, Mexico 2 8 January 18.6 2.2× Tehuacán Puebla, Mexico 2 8 January 15.2 2.2× Tula de Allende Hidalgo, Mexico 2 9 January 15.3 2.1×
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 Mexico
Number 3 of 12 episodes in Mexico since our records began, by cities reached.
Southern Mexico, January 2026 20 Southern United States and Mexico, June 2023 18 Southern Mexico, January 2026 12 Northern Mexico and United States, May 2025 12 Southern Mexico, December 2023 10 Guanajuato and Jalisco, Mexico, June 2023 10 Southern Mexico, January 2023 10 Hidalgo and Puebla, Mexico, November 2025 9 Southern United States and Mexico, March and April 2025 8 Guanajuato and Querétaro, Mexico, March 2025 8 Northern Mexico and United States, May 2023 8 Guanajuato and Jalisco, Mexico, May 2023 8 Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Southern Mexico, January 2026: 12 cities with PM2.5 at twice their usual or more, 5 to 9 January 2026, smogrank.com/episodes/2026-01-southern-mexico-2 (accessed 2 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.
