SmogRank / Thailand / Nakhon Ratchasima / Nakhon Ratchasima

Nakhon Ratchasima, month by month

Nakhon Ratchasima has a measured daily mean on 694 days since 1 January 2023. Its worst month was January 2026, at 111 US AQI (39.7 µg/m³), 86th of 2,617 cities on that month's world ranking. Its cleanest was September 2025, at 57 US AQI (12.2 µg/m³).

Every month since 2023

202677 so far249 days measured296th of 2,798 in the world
Jan111#86Feb90#258Mar85#348Apr94#205May68#328Jun58#434Jul3 daysAug62#390Sep60#413Oct69#129
2025too few days for a mean (a year needs 256)182 days measured
Jan5 daysFeb96#175Mar109#172Apr87#192May60#451Jun59#598JulnoneAug6 daysSep57#452Oct10 daysNov3 daysDec1 day
2024too few days for a mean (a year needs 257)180 days measured
Jan104#81Feb18 daysMar17 daysApr110#51May80#98Jun63#187Jul19 daysAug16 daysSep5 daysOct2 daysNov2 daysDec1 day
2023too few days for a mean (a year needs 256)83 days measured
Jan90#65Feb2 daysMar9 daysApr17 daysMay13 daysJun10 daysJul5 daysAug2 daysSep2 daysOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Nakhon Ratchasima'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 Nakhon Ratchasima 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

26 months
MonthWhy
Jul 20263 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks.
Dec 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Nov 20253 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Oct 202510 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks.
Aug 20256 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks.
Jul 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jan 20255 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks.
Dec 20241 of 31 days measured; a month needs 22. The others: 30 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 20245 of 30 days measured; a month needs 21. The others: 25 with under 18 hours of readings or readings that failed our checks.
Aug 202416 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Jul 202419 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Mar 202417 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Feb 202418 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 10 with under 18 hours of readings or readings that failed our checks.
Dec 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Sep 20232 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Aug 20232 of 31 days measured; a month needs 22. The others: 29 with under 18 hours of readings or readings that failed our checks.
Jul 20235 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 25 with under 18 hours of readings or readings that failed our checks.
Jun 202310 of 30 days measured; a month needs 21. The others: 20 with under 18 hours of readings or readings that failed our checks.
May 202313 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Apr 202317 of 30 days measured; a month needs 21. The others: 2 missing from OpenAQ's archive, 11 with under 18 hours of readings or readings that failed our checks.
Mar 20239 of 31 days measured; a month needs 22. The others: 19 missing from OpenAQ's archive, 3 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.

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

Nakhon Ratchasima's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2026 11139.7 µg/m³25 of 3186thof 2,617–
April 2024 11039.0 µg/m³27 of 3051stof 2,520–
March 2025 10938.9 µg/m³28 of 31172ndof 2,862Thailand and Laos, March 2025
January 2024 10436.6 µg/m³22 of 3181stof 2,385–
February 2025 9633.4 µg/m³28 of 28175thof 2,633–
April 2026 9432.2 µg/m³30 of 30205thof 2,941–

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.

Nakhon Ratchasima's worst days

DayUS AQIEpisode
24 Mar 2025 16777.7 µg/m³Thailand and Laos, March 2025
25 Mar 2025 16676.2 µg/m³Thailand and Laos, March 2025
1 Feb 2023 16372.4 µg/m³–
15 Feb 2024 15865.1 µg/m³–
24 Jan 2025 15663.1 µg/m³–
23 Mar 2025 15663.0 µg/m³Thailand and Laos, March 2025
25 Jan 2025 15662.6 µg/m³–
26 Jan 2025 15662.4 µg/m³–
26 Mar 2025 15662.0 µg/m³Thailand and Laos, March 2025
17 Jan 2026 15561.9 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, Nakhon Ratchasima, Thailand, 1 Jan 2023 – 12 Oct 2026. Monitor data from Air4Thai via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/th/nakhon-ratchasima/history (accessed 13 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.

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

Updated 2026-10-13 02:07 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).