SmogRank / United States / Oregon / Florence
Florence, month by month
Florence, Oregon has a measured daily mean on 1,287 days since 1 January 2023. Its worst month was September 2023, at 32 US AQI (5.8 µg/m³), 1,837th of 2,176 cities on that month's world ranking. Its cleanest was February 2024, at 12 US AQI (2.1 µg/m³). 2025 averaged 23 US AQI (4.1 µg/m³), against 21 US AQI (3.7 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
2 months
| Month | Why |
|---|---|
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 2 with readings for part of the day (a day needs 18 hours), 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Florence's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| September 2023 | 325.8 µg/m³ | 1,837thof 2,176 | – |
| September 2025 | 315.5 µg/m³ | 2,344thof 3,104 | – |
| November 2023 | 305.4 µg/m³ | 1,886thof 2,243 | – |
| October 2023 | 295.3 µg/m³ | 1,696thof 2,012 | – |
| August 2026 | 295.3 µg/m³ | 2,690thof 2,896 | North-western United States and Canada, 4 to 22 August 2026 |
| August 2025 | 274.9 µg/m³ | 2,712thof 2,901 | – |
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.
Florence's worst days
| Day | US AQI | Episode |
|---|---|---|
| 4 Aug 2026 | 8527.4 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 24 Sept 2023 | 7320.7 µg/m³ | – |
| 23 Sept 2023 | 6717.5 µg/m³ | – |
| 19 Oct 2023 | 6114.3 µg/m³ | – |
| 24 Sept 2025 | 5913.4 µg/m³ | – |
| 14 Aug 2023 | 5913.2 µg/m³ | – |
| 2 Oct 2024 | 5913.2 µg/m³ | – |
| 5 Aug 2026 | 5813.1 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 5 Jul 2024 | 5712.5 µg/m³ | – |
| 11 Aug 2025 | 5712.1 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, Florence, Oregon, 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/florence-oregon/history (accessed 12 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.
Florence 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).