SmogRank / Thailand / Tak / Mae Sot

Mae Sot, month by month

Mae Sot has a measured daily mean on 428 days since 1 January 2023. Its worst month was April 2026, at 155 US AQI (61.9 µg/m³), 40th of 2,941 cities on that month's world ranking. Its cleanest was June 2024, at 45 US AQI (8.1 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)89 days measured
Jan13 daysFeb91#248Mar21 daysApr155#40May7 daysJun7 daysJulnoneAugnoneSepnoneOctnone
2025too few days for a mean (a year needs 256)90 days measured
Jan5 daysFeb13 daysMar20 daysApr17 daysMay9 daysJunnoneJulnoneAugnoneSep6 daysOct1 dayNov4 daysDec15 days
2024too few days for a mean (a year needs 257)171 days measured
Jan19 daysFeb19 daysMar16 daysApr123#38May72#143Jun45#1,279Jul13 daysAug14 daysSep3 daysOct2 daysNov2 daysDecnone
2023too few days for a mean (a year needs 256)78 days measured
Jan114#31Feb2 daysMar9 daysApr15 daysMay14 daysJun8 daysJul5 daysAug1 daySep1 dayOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Mae Sot'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 Mae Sot 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

40 months
MonthWhy
Oct 2026No day measured. The others: 10 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks.
Sep 2026No day measured. The others: 14 with no readings from the monitor, 15 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks.
Aug 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 20267 of 30 days measured; a month needs 21. The others: 23 with under 18 hours of readings or readings that failed our checks.
May 20267 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Mar 202621 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jan 202613 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Dec 202515 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Nov 20254 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks.
Oct 20251 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks.
Sep 20256 of 30 days measured; a month needs 21. The others: 24 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.
Jul 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jun 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 20259 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Apr 202517 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks.
Mar 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Feb 202513 of 28 days measured; a month needs 20. The others: 15 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 2024No day measured. The others: 31 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 20243 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Aug 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Jul 202413 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Mar 202416 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Feb 202419 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 9 with under 18 hours of readings or readings that failed our checks.
Jan 202419 of 31 days measured; a month needs 22. The others: 12 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 20231 of 30 days measured; a month needs 21. The others: 29 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 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 20238 of 30 days measured; a month needs 21. The others: 22 with under 18 hours of readings or readings that failed our checks.
May 202314 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Apr 202315 of 30 days measured; a month needs 21. The others: 2 missing from OpenAQ's archive, 13 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.

Mae Sot's worst months

MonthUS AQIDays measuredWorld rank
April 2026 15561.9 µg/m³21 of 3040thof 2,941
April 2024 12344.5 µg/m³28 of 3038thof 2,520
January 2023 11440.7 µg/m³23 of 3131stof 1,261
February 2026 9130.6 µg/m³20 of 28248thof 2,866
May 2024 7220.4 µg/m³27 of 31143rdof 2,684
June 2024 458.1 µg/m³28 of 301,279thof 2,563

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.

Mae Sot's worst days

DayUS AQI
27 Mar 2024 183101.0 µg/m³
28 Mar 2024 17690.9 µg/m³
29 Mar 2026 17690.9 µg/m³
3 Apr 2026 17589.4 µg/m³
2 Apr 2026 17488.5 µg/m³
15 Feb 2023 17488.1 µg/m³
23 Mar 2025 17386.5 µg/m³
7 Mar 2024 17285.1 µg/m³
26 Mar 2024 17184.0 µg/m³
22 Mar 2025 17183.5 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, Mae Sot, Thailand, 1 Jan 2023 – 29 Jun 2026. Monitor data from Air4Thai via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/th/mae-sot/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.

Mae Sot 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).