SmogRank / France / Hauts-de-France / Calais

Calais, month by month

Calais has a measured daily mean on 802 days since 12 January 2023. Its worst month was March 2026, at 71 US AQI (20.1 µg/m³), 597th of 2,971 cities on that month's world ranking. Its cleanest was July 2023, at 24 US AQI (4.3 µg/m³).

Every month since 2023

202653 so far236 days measured907th of 2,793 in the world
Jan57#925Feb52#1,532Mar71#597Apr53#897May52#908Jun11 daysJul49#1,659Aug48#1,337Sep37#1,442Oct39#1,226
202553 for the year275 days measured892nd of 2,681 in the world
Jan59#597Feb16 daysMar18 daysApr61#573May20 daysJun17 daysJul38#2,041Aug41#2,059Sep34#2,057Oct20 daysNov41#1,722Dec56#996
2024too few days for a mean (a year needs 257)98 days measured
JannoneFebnoneMarnoneAprnoneMaynoneJun1 dayJul21 daysAug14 daysSepnoneOct13 daysNov57#559Dec57#654
2023too few days for a mean (a year needs 256)193 days measured
Jan9 daysFeb61#388Mar43#532Apr54#338May18 daysJun51#904Jul24#1,304Aug19 daysSepnoneOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Calais'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 Calais 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

23 months
MonthWhy
Jun 202611 of 30 days measured; a month needs 21. The others: 19 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.
Jun 202517 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks.
May 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Mar 202518 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Feb 202516 of 28 days measured; a month needs 20. The others: 12 with under 18 hours of readings or readings that failed our checks.
Oct 202413 of 31 days measured; a month needs 22. The others: 18 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.
Jul 202421 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jun 20241 of 30 days measured; a month needs 21. The others: 29 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 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 2024No day measured. The others: 31 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 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 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 202319 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
May 202318 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jan 20239 of 31 days measured; a month needs 22. The others: 11 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.

Calais's worst months

MonthUS AQIDays measuredWorld rankEpisode
March 2026 7120.1 µg/m³25 of 31597thof 2,971Europe, 18 to 25 March 2026
Europe, 1 to 12 March 2026
February 2023 6114.4 µg/m³28 of 28388thof 1,129Europe, 6 to 25 February 2023
April 2025 6114.3 µg/m³22 of 30573rdof 2,951United Kingdom and France, April 2025
January 2025 5913.2 µg/m³25 of 31597thof 2,474Germany, France and 19 more countries, January 2025
November 2024 5712.2 µg/m³27 of 30559thof 2,624Europe, November 2024
December 2024 5712.2 µg/m³22 of 31654thof 2,616Europe, 12 to 14 December 2024

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.

Calais's worst days

DayUS AQIEpisode
5 Mar 2025 14453.0 µg/m³Germany, Poland and 25 more countries, March 2025
23 Mar 2026 14051.2 µg/m³Europe, 18 to 25 March 2026
26 Jan 2026 12645.5 µg/m³Europe, January and February 2026
2 Feb 2025 12043.3 µg/m³Europe, 1 to 14 February 2025
8 Feb 2023 11742.1 µg/m³Europe, 6 to 25 February 2023
14 Feb 2023 11641.6 µg/m³Europe, 6 to 25 February 2023
9 Mar 2026 11240.0 µg/m³Europe, 1 to 12 March 2026
8 Mar 2026 11039.3 µg/m³Europe, 1 to 12 March 2026
19 Feb 2025 10737.9 µg/m³Europe, 14 February to 1 March 2025
22 Mar 2026 10537.3 µg/m³Europe, 18 to 25 March 2026

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

Calais 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).