SmogRank / Mexico / San Luis Potosí / San Luis Potosí

San Luis Potosí, month by month

San Luis Potosí has a measured daily mean on 480 days since 10 January 2023. Its worst month was April 2026, at 94 US AQI (32.0 µg/m³), 207th of 2,941 cities on that month's world ranking. Its cleanest was June 2025, at 52 US AQI (9.7 µg/m³).

Every month since 2023

202689 so far215 days measured199th of 2,793 in the world
Jan91#173Feb91#249Mar12 daysApr94#207May90#171Jun13 daysJul84#180Aug89#121Sep9 daysOct1 day
2025too few days for a mean (a year needs 256)188 days measured
JannoneFebnoneMar21 daysApr67#441May70#281Jun52#1,391Jul55#1,033AugnoneSep18 daysOct20 daysNovnoneDec20 days
2024too few days for a mean (a year needs 257)6 days measured
JannoneFebnoneMar1 dayApr5 daysMaynoneJunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
2023too few days for a mean (a year needs 256)71 days measured
Jan14 daysFeb2 daysMar10 daysApr14 daysMay4 daysJun1 dayJul6 daysAug1 daySep9 daysOct7 daysNov2 daysDec1 day
Each square is a month's mean PM2.5 in US AQI from San Luis Potosí'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 San Luis Potosí marked; each year, the year's.
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

36 months
MonthWhy
Oct 20261 of 11 days measured; a month needs 8. The others: 3 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours), 6 with readings left out by our checks.
Sep 20269 of 30 days measured; a month needs 21. The others: 21 with readings left out by our checks.
Jun 202613 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks.
Mar 202612 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Dec 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Nov 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Sep 202518 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks.
Aug 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Mar 202521 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Feb 2025No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jan 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Dec 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 2024No day measured. The others: 30 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 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 20245 of 30 days measured; a month needs 21. The others: 25 with under 18 hours of readings or readings that failed our checks.
Mar 20241 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Feb 2024No day measured. The others: 1 missing from OpenAQ's archive, 28 with under 18 hours of readings or readings that failed our checks.
Jan 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Dec 20231 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Nov 20232 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Oct 20237 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Sep 20239 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
Aug 20231 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Jul 20236 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 24 with under 18 hours of readings or readings that failed our checks.
Jun 20231 of 30 days measured; a month needs 21. The others: 29 with under 18 hours of readings or readings that failed our checks.
May 20234 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Apr 202314 of 30 days measured; a month needs 21. The others: 3 missing from OpenAQ's archive, 13 with under 18 hours of readings or readings that failed our checks.
Mar 202310 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks.
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 202314 of 31 days measured; a month needs 22. The others: 6 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.

San Luis Potosí's worst months

MonthUS AQIDays measuredWorld rankEpisode
April 2026 9432.0 µg/m³30 of 30207thof 2,941–
February 2026 9130.5 µg/m³28 of 28249thof 2,866–
January 2026 9130.4 µg/m³29 of 31173rdof 2,617Southern Mexico, January 2026
May 2026 9030.2 µg/m³31 of 31171stof 2,874–
August 2026 8929.3 µg/m³31 of 31121stof 2,896–
July 2026 8427.0 µg/m³31 of 31180thof 2,784–

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.

San Luis Potosí's worst days

DayUS AQIEpisode
1 Jan 2026 17184.0 µg/m³Southern Mexico, January 2026
27 Apr 2023 15866.1 µg/m³–
4 Sept 2023 15156.1 µg/m³–
8 May 2026 14452.8 µg/m³–
20 Apr 2026 13248.2 µg/m³–
11 Oct 2023 12746.2 µg/m³–
18 Apr 2024 12746.1 µg/m³–
18 Feb 2026 12143.5 µg/m³–
19 May 2026 11842.6 µg/m³–
30 Apr 2024 11842.3 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, San Luis Potosí, Mexico, 10 Jan 2023 – 1 Oct 2026. Monitor data from Sinaica Mexico via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/mx/san-luis-potosi/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.

San Luis Potosí 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).