SmogRank / French Guiana / Guyane / Kourou

Kourou, month by month

Kourou has a measured daily mean on 734 days since 11 January 2023. Its worst month was February 2024, at 80 US AQI (24.7 µg/m³), 141st of 2,486 cities on that month's world ranking. Its cleanest was July 2025, at 18 US AQI (3.3 µg/m³).

Every month since 2023

202649 so far237 days measured1,371st of 2,793 in the world
Jan12 daysFeb78#436Mar39#2,362Apr55#789May45#1,281Jun17 daysJul28#2,595Aug47#1,422Sep38#1,314Oct27#2,247
2025too few days for a mean (a year needs 256)246 days measured
Jan21 daysFeb58#961Mar52#1,686Apr54#1,032May16 daysJun12 daysJul18#2,830Aug28#2,682Sep49#918Oct20 daysNov33#2,174Dec13 days
2024too few days for a mean (a year needs 257)195 days measured
Jan3 daysFeb80#141Mar15 daysApr65#331May52#832Jun2 daysJul31#2,131Aug12 daysSepnoneOct12 daysNov26#2,357Dec58#595
2023too few days for a mean (a year needs 256)56 days measured
Jan7 daysFeb53#650Mar20 daysApr3 daysMaynoneJunnoneJul1 dayAugnoneSepnoneOctnoneNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Kourou'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 Kourou 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.
Jan 202612 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Dec 202513 of 31 days measured; a month needs 22. The others: 18 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 202512 of 30 days measured; a month needs 21. The others: 18 with under 18 hours of readings or readings that failed our checks.
May 202516 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Jan 202521 of 31 days measured; a month needs 22. The others: 10 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 202412 of 31 days measured; a month needs 22. The others: 19 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.
Mar 202415 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Jan 20243 of 31 days measured; a month needs 22. The others: 28 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 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: 30 with under 18 hours of readings or readings that failed our checks.
Jun 2023No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
May 2023No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 20233 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks.
Mar 202320 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jan 20237 of 31 days measured; a month needs 22. The others: 14 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.

Kourou's worst months

MonthUS AQIDays measuredWorld rank
February 2024 8024.7 µg/m³23 of 29141stof 2,486
February 2026 7823.4 µg/m³23 of 28436thof 2,866
April 2024 6516.8 µg/m³26 of 30331stof 2,520
December 2024 5813.0 µg/m³23 of 31595thof 2,616
February 2025 5813.0 µg/m³22 of 28961stof 2,633
April 2026 5511.1 µg/m³29 of 30789thof 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.

Kourou's worst days

DayUS AQI
31 Jan 2024 187107.0 µg/m³
22 Feb 2026 184102.0 µg/m³
30 Jan 2024 18096.6 µg/m³
21 Feb 2026 15561.9 µg/m³
20 Apr 2024 14754.3 µg/m³
24 Dec 2024 13850.5 µg/m³
23 Dec 2024 13448.7 µg/m³
19 Apr 2024 13147.8 µg/m³
6 May 2024 13047.2 µg/m³
1 Feb 2024 12946.9 µg/m³

Daily means, the highest since 11 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, Kourou, French Guiana, 11 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/gf/kourou/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.

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

Updated 2026-10-12 21:07 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).