SmogRank / United States / Washington / Port Townsend
Port Townsend, month by month
Port Townsend has a measured daily mean on 1,282 days since 1 January 2023. Its worst month was August 2023, at 40 US AQI (7.2 µg/m³), 1,258th of 1,980 cities on that month's world ranking. Its cleanest was May 2025, at 17 US AQI (3.1 µg/m³). 2025 averaged 23 US AQI (4.2 µg/m³), against 24 US AQI (4.3 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 | 7 of 31 days measured; a month needs 22. The others: 2 with no readings from the monitor, 2 with readings for part of the day (a day needs 18 hours), 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.
Port Townsend's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2023 | 407.2 µg/m³ | 1,258thof 1,980 | North-western United States and Canada, August 2023 |
| January 2025 | 397.1 µg/m³ | 1,673rdof 2,474 | – |
| November 2023 | 386.9 µg/m³ | 1,467thof 2,243 | – |
| December 2024 | 325.8 µg/m³ | 2,116thof 2,616 | – |
| January 2026 | 325.8 µg/m³ | 2,174thof 2,617 | – |
| November 2024 | 295.2 µg/m³ | 2,239thof 2,624 | – |
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.
Port Townsend's worst days
| Day | US AQI | Episode |
|---|---|---|
| 26 Aug 2023 | 8829.0 µg/m³ | North-western United States and Canada, August 2023 |
| 25 Aug 2023 | 7120.1 µg/m³ | North-western United States and Canada, August 2023 |
| 27 Aug 2023 | 7019.5 µg/m³ | North-western United States and Canada, August 2023 |
| 20 Aug 2023 | 6919.0 µg/m³ | North-western United States and Canada, August 2023 |
| 28 Aug 2023 | 6315.8 µg/m³ | North-western United States and Canada, August 2023 |
| 21 Jan 2025 | 5913.3 µg/m³ | – |
| 29 Jan 2025 | 5913.3 µg/m³ | – |
| 26 Jan 2026 | 5812.8 µg/m³ | – |
| 1 Jan 2026 | 5812.7 µg/m³ | – |
| 4 Dec 2024 | 5812.6 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, Port Townsend, 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/port-townsend/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.
Port Townsend 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).