SmogRank / Episodes / Mexico

Guanajuato, Mexico, December 2024

For 1 day, on 25 December 2024, 9 cities in Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Ciudad Nezahualcoyotl, México, Mexico: 78.0 µg/m³ on 25 December, about 2.6× its usual 30.4.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 1 country
Days125 December 2024
Worst day25 December9 cities counted
Furthest above usual3.9×Irapuato

Day by day

25 December 9 cities at twice their usual or more
Santiago de QuerétaroSan Juan del RíoSalamancaMoreliaGuanajuatoXonacatlánNaucalpan de JuárezEcatepec de MorelosCholulaSan Luis de la PazAbasoloMexico CitySan Miguel de AllendeLeón de los AldamaCiudad NezahualcoyotlSilao de la VictoriaCelayaIrapuato
22 Dec232425262728
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

Ciudad Nezahualcoyo…Ciudad Nezahualcoyotl, 22 December: no readingCiudad Nezahualcoyotl, 23 December: 22.1 µg/m³, 0.7× usualCiudad Nezahualcoyotl, 24 December: 30.5 µg/m³, 1.0× usualCiudad Nezahualcoyotl, 25 December: 78.0 µg/m³, 2.6× usualCiudad Nezahualcoyotl, 26 December: 22.6 µg/m³, 0.7× usualCiudad Nezahualcoyotl, 27 December: 25.0 µg/m³, 0.8× usualCiudad Nezahualcoyotl, 28 December: 26.4 µg/m³, 0.9× usualIrapuatoIrapuato, 22 December: 12.1 µg/m³, 0.6× usualIrapuato, 23 December: 24.1 µg/m³, 1.3× usualIrapuato, 24 December: 37.0 µg/m³, 1.9× usualIrapuato, 25 December: 73.7 µg/m³, 3.9× usualIrapuato, 26 December: 29.6 µg/m³, 1.6× usualIrapuato, 27 December: 35.4 µg/m³, 1.9× usualIrapuato, 28 December: 40.3 µg/m³, 2.1× usualCelayaCelaya, 22 December: 7.8 µg/m³, 0.4× usualCelaya, 23 December: 14.4 µg/m³, 0.8× usualCelaya, 24 December: 21.9 µg/m³, 1.2× usualCelaya, 25 December: 65.2 µg/m³, 3.5× usualCelaya, 26 December: 19.0 µg/m³, 1.0× usualCelaya, 27 December: 25.6 µg/m³, 1.4× usualCelaya, 28 December: 32.1 µg/m³, 1.7× usualSilao de la VictoriaSilao de la Victoria, 22 December: 14.4 µg/m³, 0.7× usualSilao de la Victoria, 23 December: 21.4 µg/m³, 1.1× usualSilao de la Victoria, 24 December: 34.6 µg/m³, 1.7× usualSilao de la Victoria, 25 December: 62.9 µg/m³, 3.2× usualSilao de la Victoria, 26 December: 26.1 µg/m³, 1.3× usualSilao de la Victoria, 27 December: 28.4 µg/m³, 1.4× usualSilao de la Victoria, 28 December: 32.1 µg/m³, 1.6× usualMexico CityMexico City, 22 December: 11.5 µg/m³, 0.5× usualMexico City, 23 December: 17.1 µg/m³, 0.7× usualMexico City, 24 December: 24.9 µg/m³, 1.1× usualMexico City, 25 December: 52.6 µg/m³, 2.3× usualMexico City, 26 December: 20.0 µg/m³, 0.9× usualMexico City, 27 December: 17.4 µg/m³, 0.7× usualMexico City, 28 December: 18.9 µg/m³, 0.8× usualLeón de los AldamaLeón de los Aldama, 22 December: 12.8 µg/m³, 0.7× usualLeón de los Aldama, 23 December: 18.7 µg/m³, 1.1× usualLeón de los Aldama, 24 December: 29.9 µg/m³, 1.7× usualLeón de los Aldama, 25 December: 42.2 µg/m³, 2.5× usualLeón de los Aldama, 26 December: 19.7 µg/m³, 1.1× usualLeón de los Aldama, 27 December: 22.7 µg/m³, 1.3× usualLeón de los Aldama, 28 December: 35.0 µg/m³, 2.0× usualAbasoloAbasolo, 22 December: no readingAbasolo, 23 December: no readingAbasolo, 24 December: 23.4 µg/m³, 1.7× usualAbasolo, 25 December: 30.0 µg/m³, 2.1× usualAbasolo, 26 December: 14.0 µg/m³, 1.0× usualAbasolo, 27 December: 19.4 µg/m³, 1.4× usualAbasolo, 28 December: 26.7 µg/m³, 1.9× usualSan Miguel de Allen…San Miguel de Allende, 22 December: 8.1 µg/m³, 0.7× usualSan Miguel de Allende, 23 December: 12.7 µg/m³, 1.1× usualSan Miguel de Allende, 24 December: 21.0 µg/m³, 1.9× usualSan Miguel de Allende, 25 December: 27.6 µg/m³, 2.4× usualSan Miguel de Allende, 26 December: 15.7 µg/m³, 1.4× usualSan Miguel de Allende, 27 December: 19.0 µg/m³, 1.7× usualSan Miguel de Allende, 28 December: 17.6 µg/m³, 1.6× usualSan Luis de la PazSan Luis de la Paz, 22 December: 8.7 µg/m³, 0.6× usualSan Luis de la Paz, 23 December: 16.2 µg/m³, 1.2× usualSan Luis de la Paz, 24 December: 18.9 µg/m³, 1.4× usualSan Luis de la Paz, 25 December: 27.6 µg/m³, 2.0× usualSan Luis de la Paz, 26 December: 23.9 µg/m³, 1.7× usualSan Luis de la Paz, 27 December: 32.5 µg/m³, 2.4× usualSan Luis de la Paz, 28 December: 28.2 µg/m³, 2.1× usual22 Dec232425262728
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
IrapuatoGuanajuato, Mexico1 73.725 December19.03.9×
CelayaGuanajuato, Mexico1 65.225 December18.43.5×
Silao de la VictoriaGuanajuato, Mexico1 62.925 December19.93.2×
Ciudad NezahualcoyotlMéxico, Mexico1 78.025 December30.42.6×
León de los AldamaGuanajuato, Mexico1 42.225 December17.22.5×
San Miguel de AllendeGuanajuato, Mexico1 27.625 December11.32.4×
San Luis de la PazGuanajuato, Mexico1 32.527 December13.72.4×
Mexico CityMexico City, Mexico1 52.625 December23.32.3×
AbasoloGuanajuato, Mexico1 30.025 December14.12.1×

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 10 of 16 episodes in Mexico since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 16.

Use this page

SmogRank, Guanajuato, Mexico, December 2024: 9 cities with PM2.5 at twice their usual or more, 25 December 2024, smogrank.com/episodes/2024-12-guanajuato-mexico (accessed 3 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.