SmogRank / United States / Montana / Bozeman
Bozeman, month by month
Bozeman has a measured daily mean on 1,233 days since 1 January 2023. Its worst month was August 2026, at 67 US AQI (17.9 µg/m³), 297th of 2,896 cities on that month's world ranking. Its cleanest was June 2023, at 20 US AQI (3.6 µg/m³). 2025 averaged 42 US AQI (7.5 µg/m³), against 41 US AQI (7.3 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
4 months
| Month | Why |
|---|---|
| Aug 2025 | 10 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| Jul 2024 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Bozeman's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2026 | 6717.9 µg/m³ | 297thof 2,896 | North-western United States and Canada, 4 to 22 August 2026 North-western United States and Canada, July and August 2026 |
| February 2025 | 5612.0 µg/m³ | 1,018thof 2,633 | – |
| September 2024 | 5511.0 µg/m³ | 344thof 2,010 | North-western United States and Canada, 4 to 11 September 2024 North-western United States and Canada, 10 to 11 September 2024 |
| January 2025 | 5310.2 µg/m³ | 960thof 2,474 | – |
| October 2024 | 5310.0 µg/m³ | 524thof 2,020 | – |
| August 2024 | 529.5 µg/m³ | 722ndof 2,010 | – |
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.
Bozeman's worst days
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, Bozeman, United States, 1 Jan 2023 – 10 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/bozeman/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.
Bozeman 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).