SmogRank / France / Occitanie / Castres

Castres, month by month

Castres has a measured daily mean on 632 days since 14 July 2023. Its worst month was January 2024, at 68 US AQI (18.4 µg/m³), 321st of 2,385 cities on that month's world ranking. Its cleanest was September 2025, at 23 US AQI (4.1 µg/m³).

Every month since 2023

202643 so far218 days measured1,913th of 2,793 in the world
Jan17 daysFeb18 daysMar41#2,272Apr30#2,400May21 daysJun17 daysJul55#1,114Aug50#1,181Sep30#2,116Oct27#2,182
2025too few days for a mean (a year needs 256)214 days measured
Jan19 daysFeb56#1,023Mar42#2,011Apr18 daysMay14 daysJun9 daysJul17 daysAug48#1,605Sep23#2,920Oct12 daysNov16 daysDec20 days
2024too few days for a mean (a year needs 257)170 days measured
Jan68#321Feb54#602Mar10 daysApr2 daysMaynoneJun2 daysJul37#1,819Aug14 daysSepnoneOct12 daysNov55#626Dec61#516
2023too few days for a mean (a year needs 256)30 days measured
JanFebMarAprMayJunJul1 dayAugnoneSepnoneOctnoneNovnoneDec60#311
Each square is a month's mean PM2.5 in US AQI from Castres'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 Castres 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

24 months
MonthWhy
Jun 202617 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks.
May 202621 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Feb 202618 of 28 days measured; a month needs 20. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jan 202617 of 31 days measured; a month needs 22. The others: 14 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 202516 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Oct 202512 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Jul 202517 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Jun 20259 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
May 202514 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Apr 202518 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks.
Jan 202519 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Oct 202412 of 31 days measured; a month needs 22. The others: 19 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 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Jun 20242 of 30 days measured; a month needs 21. The others: 28 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 20242 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks.
Mar 202410 of 31 days measured; a month needs 22. The others: 21 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 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Jul 20231 of 31 days measured; a month needs 22. The others: 17 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.

Castres's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2024 6818.4 µg/m³29 of 31321stof 2,385Europe, 8 to 27 January 2024
Western Europe, January 2024and 1 more
December 2024 6114.2 µg/m³22 of 31516thof 2,616Europe, 24 December 2024 to 3 January 2025
December 2023 6014.1 µg/m³29 of 31311thof 2,247Spain, France and 2 more countries, December 2023 to January 2024
February 2025 5611.9 µg/m³20 of 281,023rdof 2,633–
November 2024 5511.5 µg/m³25 of 30626thof 2,624–
July 2026 5511.0 µg/m³30 of 311,114thof 2,784France, July 2026

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.

Castres's worst days

DayUS AQIEpisode
14 Jan 2024 10436.7 µg/m³Europe, 8 to 27 January 2024
Western Europe, January 2024
10 Jan 2024 10035.2 µg/m³Europe, 8 to 27 January 2024
15 Aug 2026 8929.3 µg/m³–
11 Jan 2024 8829.1 µg/m³Europe, 8 to 27 January 2024
20 Jan 2024 8829.1 µg/m³Europe, 8 to 27 January 2024
9 Jan 2024 8828.9 µg/m³Europe, 8 to 27 January 2024
26 Jul 2026 8828.8 µg/m³France, July 2026
29 Dec 2023 8628.0 µg/m³Spain, France and 2 more countries, December 2023 to January 2024
27 Dec 2024 8627.9 µg/m³Europe, 24 December 2024 to 3 January 2025
25 Jul 2026 8627.8 µg/m³France, July 2026

Daily means, the highest since 14 Jul 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, Castres, France, 14 Jul 2023 – 12 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/fr/castres/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.

Castres 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).