SmogRank / United States / Colorado / Brighton
Brighton, month by month
Brighton, Colorado has a measured daily mean on 447 days since 14 August 2024. Its worst month was August 2025, at 52 US AQI (9.7 µg/m³), 1,311th of 2,901 cities on that month's world ranking. Its cleanest was March 2025, at 28 US AQI (5.1 µg/m³).
Every month since 2024
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
19 months
| Month | Why |
|---|---|
| Oct 2026 | 7 of 11 days measured; a month needs 8. The others: 4 with readings for part of the day (a day needs 18 hours). |
| Sep 2026 | 17 of 30 days measured; a month needs 21. The others: 5 with readings for part of the day (a day needs 18 hours), 8 with under 18 hours of readings or readings that failed our checks. |
| Aug 2026 | 8 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 7 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| May 2026 | 5 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | 2 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Mar 2026 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Feb 2026 | 16 of 28 days measured; a month needs 20. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Dec 2025 | 17 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Jul 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. |
| Jun 2025 | 6 of 30 days measured; a month needs 21. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| May 2025 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | 17 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 15 of 28 days measured; a month needs 20. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | 16 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | 12 of 31 days measured; a month needs 22. The others: 6 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.
Brighton's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2025 | 529.7 µg/m³ | 1,311thof 2,901 | – |
| October 2024 | 529.5 µg/m³ | 572ndof 2,020 | – |
| September 2025 | 478.4 µg/m³ | 1,085thof 3,104 | Colorado and Wyoming, United States, September 2025 |
| November 2024 | 437.7 µg/m³ | 1,444thof 2,624 | – |
| December 2024 | 356.3 µg/m³ | 1,963rdof 2,616 | – |
| January 2026 | 356.3 µg/m³ | 2,028thof 2,617 | – |
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.
Brighton's worst days
| Day | US AQI | Episode |
|---|---|---|
| 4 Sept 2025 | 8326.3 µg/m³ | Colorado and Wyoming, United States, September 2025 |
| 14 Feb 2025 | 8226.0 µg/m³ | – |
| 13 Feb 2025 | 8024.5 µg/m³ | – |
| 17 Feb 2025 | 7823.8 µg/m³ | – |
| 6 Sept 2025 | 7421.6 µg/m³ | – |
| 7 Oct 2024 | 7421.2 µg/m³ | – |
| 8 Oct 2024 | 7321.1 µg/m³ | – |
| 5 Sept 2025 | 7321.0 µg/m³ | – |
| 6 Aug 2025 | 6919.0 µg/m³ | – |
| 11 Oct 2024 | 6918.9 µg/m³ | – |
Daily means, the highest since 14 Aug 2024; 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, Brighton, Colorado, United States, 14 Aug 2024 – 11 Oct 2026. Monitor data from Clarity via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/us/brighton-colorado/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.
Brighton now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 05:07 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).