SmogRank / United States / Idaho / Preston
Preston, month by month
Preston, Idaho has a measured daily mean on 1,243 days since 1 January 2023. Its worst month was January 2024, at 53 US AQI (10.2 µg/m³), 859th of 2,385 cities on that month's world ranking. Its cleanest was March 2025, at 12 US AQI (2.2 µg/m³). 2025 averaged 23 US AQI (4.1 µg/m³), against 31 US AQI (5.6 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 |
|---|---|
| Oct 2026 | 4 of 11 days measured; a month needs 8. The others: 1 with no readings from the monitor, 6 with readings for part of the day (a day needs 18 hours). |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 1 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.
Preston's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2024 | 5310.2 µg/m³ | 859thof 2,385 | – |
| July 2024 | 488.6 µg/m³ | 1,137thof 2,566 | – |
| December 2023 | 478.5 µg/m³ | 1,105thof 2,247 | – |
| December 2024 | 478.5 µg/m³ | 1,212thof 2,616 | – |
| August 2024 | 447.9 µg/m³ | 1,276thof 2,010 | North-western United States, August and September 2024 Oregon, Idaho and Utah, United States, August 2024 |
| November 2023 | 437.7 µg/m³ | 1,236thof 2,243 | – |
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.
Preston's worst days
| Day | US AQI | Episode |
|---|---|---|
| 8 Aug 2024 | 8728.5 µg/m³ | Oregon, Idaho and Utah, United States, August 2024 |
| 30 Aug 2024 | 8426.8 µg/m³ | North-western United States, August and September 2024 |
| 1 Feb 2023 | 8326.4 µg/m³ | Utah and Idaho, United States, February 2023 |
| 4 Sept 2024 | 8125.0 µg/m³ | North-western United States and Canada, 4 to 11 September 2024 |
| 30 Aug 2023 | 7823.7 µg/m³ | – |
| 17 Jan 2024 | 7723.0 µg/m³ | – |
| 23 Jan 2024 | 7622.3 µg/m³ | – |
| 29 Aug 2024 | 7522.1 µg/m³ | North-western United States, August and September 2024 |
| 30 Nov 2023 | 7320.9 µg/m³ | – |
| 3 Aug 2026 | 7120.0 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, Preston, Idaho, United States, 1 Jan 2023 – 9 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/preston/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.
Preston now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 19:07 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).