SmogRank / Mexico / Guanajuato / Guanajuato

Guanajuato, month by month

Guanajuato has a measured daily mean on 889 days since 1 January 2023. Its worst month was May 2023, at 77 US AQI (22.8 µg/m³), 91st of 1,600 cities on that month's world ranking. Its cleanest was October 2023, at 47 US AQI (8.4 µg/m³).

Every month since 2023

202656 so far210 days measured740th of 2,793 in the world
Jan58#867Feb13 daysMar59#1,027Apr60#626May20 daysJun14 daysJul53#1,303Aug54#755Sep20 daysOct29#2,075
2025too few days for a mean (a year needs 256)193 days measured
Jan59#586Feb62#869Mar67#700Apr14 daysMay14 daysJun14 daysJul9 daysAug7 daysSep9 daysOct18 daysNov19 daysDec12 days
2024too few days for a mean (a year needs 257)218 days measured
Jan54#814Feb55#529Mar58#238Apr19 daysMay74#127Jun16 daysJulnoneAugnoneSep1 dayOct54#455Nov60#460Dec59#563
202358 for the year268 days measured171st of 1,355 in the world
Jan12 daysFeb2 daysMar11 daysApr66#138May77#91Jun64#350Jul54#552Aug54#509Sep52#607Oct47#649Nov52#643Dec52#769
Each square is a month's mean PM2.5 in US AQI from Guanajuato's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Guanajuato marked; each year, the year's. A dashed square is the running month, so far.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Months without a mean, and why

21 months
MonthWhy
Sep 202620 of 30 days measured; a month needs 21. The others: 3 with no readings from the monitor, 7 with readings for part of the day (a day needs 18 hours).
Jun 202614 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
May 202620 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Feb 202613 of 28 days measured; a month needs 20. The others: 15 with under 18 hours of readings or readings that failed our checks.
Dec 202512 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Nov 202519 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Oct 202518 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Sep 20259 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
Aug 20257 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Jul 20259 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Jun 202514 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
May 202514 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Apr 202514 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Sep 20241 of 30 days measured; a month needs 21. The others: 29 with under 18 hours of readings or readings that failed our checks.
Aug 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 202416 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Apr 202419 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Mar 202311 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive.
Feb 20232 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks.
Jan 202312 of 31 days measured; a month needs 22. The others: 6 missing from OpenAQ's archive, 13 with under 18 hours of readings or readings that failed our checks.

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Guanajuato's worst months

MonthUS AQIDays measuredWorld rankEpisode
May 2023 7722.8 µg/m³28 of 3191stof 1,600Guanajuato and Jalisco, Mexico, May 2023
May 2024 7421.5 µg/m³24 of 31127thof 2,684–
March 2025 6717.9 µg/m³27 of 31700thof 2,862Southern Mexico, March 2025
April 2023 6617.2 µg/m³26 of 30138thof 1,622–
June 2023 6416.3 µg/m³27 of 30350thof 1,603Southern Mexico, June 2023
February 2025 6214.9 µg/m³22 of 28869thof 2,633–

Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.

Guanajuato's worst days

DayUS AQIEpisode
4 May 2023 11641.5 µg/m³Guanajuato and Jalisco, Mexico, May 2023
20 Mar 2025 11641.4 µg/m³Southern Mexico, March 2025
5 May 2023 11541.3 µg/m³Guanajuato and Jalisco, Mexico, May 2023
3 May 2023 10135.7 µg/m³Guanajuato and Jalisco, Mexico, May 2023
19 Apr 2024 9935.0 µg/m³–
7 Jun 2024 9734.0 µg/m³Southern Mexico, June 2024
2 May 2023 9331.9 µg/m³–
6 May 2024 9331.7 µg/m³–
18 Feb 2025 9130.4 µg/m³–
12 May 2024 9029.9 µg/m³–

Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.

Use this history

SmogRank, PM2.5 monthly and daily means, Guanajuato, Mexico, 1 Jan 2023 – 11 Oct 2026. Monitor data from Sinaica Mexico via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/mx/guanajuato/history (accessed 12 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

Guanajuato now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 23:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).