SmogRank / United States / Oregon / Coos Bay
Coos Bay, month by month
Coos Bay has a measured daily mean on 1,268 days since 1 January 2023. Its worst month was November 2024, at 44 US AQI (7.9 µg/m³), 1,384th of 2,624 cities on that month's world ranking. Its cleanest was July 2023, at 12 US AQI (2.2 µg/m³). 2025 averaged 22 US AQI (3.9 µg/m³), against 22 US AQI (4.0 µg/m³) in 2024.
Every month since 2023
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
3 months
| Month | Why |
|---|---|
| May 2025 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 9 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 2 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.
Coos Bay's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| November 2024 | 447.9 µg/m³ | 1,384thof 2,624 | North-western United States and Canada, November 2024 |
| November 2023 | 417.4 µg/m³ | 1,320thof 2,243 | – |
| November 2025 | 376.7 µg/m³ | 1,959thof 2,715 | – |
| January 2026 | 376.7 µg/m³ | 1,901stof 2,617 | – |
| December 2024 | 346.2 µg/m³ | 1,990thof 2,616 | – |
| October 2023 | 315.6 µg/m³ | 1,615thof 2,012 | – |
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.
Coos Bay's worst days
| Day | US AQI | Episode |
|---|---|---|
| 7 Nov 2024 | 12545.2 µg/m³ | North-western United States and Canada, November 2024 |
| 8 Nov 2024 | 10035.3 µg/m³ | North-western United States and Canada, November 2024 |
| 9 Nov 2024 | 9331.9 µg/m³ | North-western United States and Canada, November 2024 |
| 9 Nov 2023 | 7722.8 µg/m³ | – |
| 4 Dec 2024 | 7320.8 µg/m³ | – |
| 4 Aug 2026 | 7019.3 µg/m³ | – |
| 5 Dec 2024 | 6617.2 µg/m³ | – |
| 10 Nov 2024 | 6516.5 µg/m³ | North-western United States and Canada, November 2024 |
| 8 Nov 2025 | 6516.5 µg/m³ | – |
| 1 Nov 2023 | 6315.7 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, Coos Bay, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/coos-bay/history (accessed 13 Oct 2026).
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.
Coos Bay now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 04:07 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).