SmogRank / Mexico / Querétaro / Santiago de Querétaro

Santiago de Querétaro, month by month

Santiago de Querétaro has a measured daily mean on 802 days since 10 January 2023. Its worst month was May 2025, at 73 US AQI (21.1 µg/m³), 244th of 2,826 cities on that month's world ranking. Its cleanest was September 2025, at 46 US AQI (8.3 µg/m³).

Every month since 2023

202663 so far281 days measured523rd of 2,793 in the world
Jan70#483Feb72#549Mar68#664Apr67#477May72#276Jun54#587Jul59#682Aug59#451Sep54#567Oct36#1,599
202560 for the year257 days measured474th of 2,681 in the world
Jan7 daysFeb1 dayMarnoneApr5 daysMay73#244Jun53#1,216Jul57#753Aug55#1,001Sep46#1,119Oct55#481Nov67#480Dec64#688
2024too few days for a mean (a year needs 257)61 days measured
Jan15 daysFeb6 daysMar3 daysApr3 daysMay10 daysJun9 daysJul3 daysAug3 daysSep1 dayOct2 daysNov2 daysDec4 days
2023too few days for a mean (a year needs 256)203 days measured
Jan13 daysFeb2 daysMar11 daysApr71#112May5 daysJun4 daysJul18 daysAug53#592Sep55#401Oct12 daysNov54#444Dec57#407
Each square is a month's mean PM2.5 in US AQI from Santiago de Querétaro'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 Santiago de Querétaro 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

23 months
MonthWhy
Apr 20255 of 30 days measured; a month needs 21. The others: 25 with under 18 hours of readings or readings that failed our checks.
Mar 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 20251 of 28 days measured; a month needs 20. The others: 27 with under 18 hours of readings or readings that failed our checks.
Jan 20257 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Dec 20244 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Nov 20242 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Oct 20242 of 31 days measured; a month needs 22. The others: 29 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 20243 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jul 20243 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jun 20249 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
May 202410 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks.
Apr 20243 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Mar 20243 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Feb 20246 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 22 with under 18 hours of readings or readings that failed our checks.
Jan 202415 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Oct 202312 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Jul 202318 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 12 with under 18 hours of readings or readings that failed our checks.
Jun 20234 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks.
May 20235 of 31 days measured; a month needs 22. The others: 26 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 202313 of 31 days measured; a month needs 22. The others: 7 missing from OpenAQ's archive, 2 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.

Santiago de Querétaro's worst months

MonthUS AQIDays measuredWorld rankEpisode
May 2025 7321.1 µg/m³31 of 31244thof 2,826–
February 2026 7220.2 µg/m³28 of 28549thof 2,866–
May 2026 7220.2 µg/m³31 of 31276thof 2,874–
April 2023 7119.9 µg/m³27 of 30112thof 1,622–
January 2026 7019.2 µg/m³31 of 31483rdof 2,617Mexico, January 2026
Southern Mexico, January 2026
March 2026 6818.3 µg/m³31 of 31664thof 2,971–

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.

Santiago de Querétaro's worst days

DayUS AQIEpisode
1 Jan 2024 15561.9 µg/m³Southern Mexico, January 2024
25 Dec 2023 12244.0 µg/m³Southern Mexico, December 2023
6 Jan 2026 11842.3 µg/m³Mexico, January 2026
8 Jan 2026 11139.5 µg/m³Mexico, January 2026
7 Jun 2024 10537.0 µg/m³Southern Mexico, June 2024
4 May 2023 10436.6 µg/m³–
25 Apr 2024 10236.0 µg/m³–
3 May 2023 10235.8 µg/m³–
21 Nov 2025 10035.3 µg/m³Hidalgo, Puebla and Querétaro, Mexico, November 2025
11 May 2024 10035.2 µg/m³–

Daily means, the highest since 10 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, Santiago de Querétaro, Mexico, 10 Jan 2023 – 11 Oct 2026. Monitor data from Sinaica Mexico via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/mx/santiago-de-queretaro/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.

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

Updated 2026-10-12 22:07 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).