SmogRank / Thailand / Ratchaburi / Ratchaburi

Ratchaburi, month by month

Ratchaburi has a measured daily mean on 724 days since 1 January 2023. Its worst month was January 2024, at 150 US AQI (55.4 µg/m³), 25th of 2,385 cities on that month's world ranking. Its cleanest was September 2025, at 54 US AQI (10.8 µg/m³).

Every month since 2023

202684 so far230 days measured236th of 2,791 in the world
Jan121#68Feb107#168Mar94#217Apr102#167May67#335Jun59#406Jul3 daysAug60#423Sep19 daysOctnone
2025too few days for a mean (a year needs 256)211 days measured
Jan5 daysFeb123#63Mar106#184Apr73#313May60#463Jun60#547JulnoneAug4 daysSep54#586Oct10 daysNov12 daysDec90#310
2024too few days for a mean (a year needs 257)194 days measured
Jan150#25Feb114#59Mar18 daysApr98#62May78#105Jun60#238Jul16 daysAug19 daysSep5 daysOct2 daysNov4 daysDecnone
2023too few days for a mean (a year needs 256)89 days measured
Jan129#25Feb2 daysMar9 daysApr19 daysMay15 daysJun10 daysJul6 daysAug2 daysSep3 daysOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Ratchaburi'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 Ratchaburi 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

26 months
MonthWhy
Oct 2026No day measured. The others: 11 with no readings from the monitor, 1 with under 18 hours of readings or readings that failed our checks.
Sep 202619 of 30 days measured; a month needs 21. The others: 10 with no readings from the monitor, 1 with under 18 hours of readings or readings that failed our checks.
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.
Nov 202512 of 30 days measured; a month needs 21. The others: 18 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 20254 of 31 days measured; a month needs 22. The others: 27 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 2024No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 20244 of 30 days measured; a month needs 21. The others: 26 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 202419 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Jul 202416 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Mar 202418 of 31 days measured; a month needs 22. The others: 13 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 20233 of 30 days measured; a month needs 21. The others: 27 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 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 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 202315 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Apr 202319 of 30 days measured; a month needs 21. The others: 2 missing from OpenAQ's archive, 9 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.

Ratchaburi's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2024 15055.4 µg/m³23 of 3125thof 2,385–
January 2023 12947.0 µg/m³23 of 3125thof 1,261–
February 2025 12344.4 µg/m³28 of 2863rdof 2,633–
January 2026 12143.5 µg/m³31 of 3168thof 2,617–
February 2024 11440.6 µg/m³23 of 2959thof 2,486Thailand, February 2024
February 2026 10737.9 µg/m³28 of 28168thof 2,866–

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.

Ratchaburi's worst days

DayUS AQIEpisode
15 Feb 2024 17691.5 µg/m³Thailand, February 2024
1 Feb 2023 17386.6 µg/m³–
24 Jan 2025 17285.0 µg/m³–
14 Feb 2024 17184.6 µg/m³Thailand, February 2024
24 Jan 2023 16778.0 µg/m³–
13 Feb 2024 16271.1 µg/m³Thailand, February 2024
16 Apr 2023 16270.8 µg/m³Thailand, April 2023
28 Jan 2024 16169.8 µg/m³–
30 Jan 2024 16068.8 µg/m³–
25 Jan 2025 16068.6 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, Ratchaburi, Thailand, 1 Jan 2023 – 19 Sep 2026. Monitor data from Air4Thai via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/th/ratchaburi/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.

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

Updated 2026-10-12 17:07 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).