Current 8-Hour Ozone Summary
2026 season at a glance
Count of calendar days in the 2026 ozone season exceeding each level.
- Days > 70 ppb
- 66
- Days > 75 ppb
- 42
- Days > 80 ppb
- 16
- Days > 84 ppb
- 5
- Days > 65 ppb
- 96
- Days > 60 ppb
- 121
Ozone Summary through September 14th, 2026
Under each 2026 value: the date it was recorded and the smoke impact probability (note ^^).
- Exceeds 70 ppb 2015 standard
- Exceeds 75 ppb 2008 standard
| Monitor | 1st Max 2026 | 2nd Max 2026 | 3rd Max 2026 | 4th Max 2026 | 4th Max 2025 | 4th Max 2024 | 2024–2026 Estimated Average^ |
|---|---|---|---|---|---|---|---|
| ***Aurora East | 78, above 75 ppb05/11/26Smoke: None | 77, above 75 ppb04/20/26Smoke: None | 75, above 70 ppb05/16/26Smoke: None | 74, above 70 ppb07/06/26Smoke: High | 70 | 81, above 75 ppb | 75, above 70 ppb |
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| Blackhawk | 86, above 75 ppb08/07/26Smoke: Moderate | 80, above 75 ppb08/08/26Smoke: High | 75, above 70 ppb07/31/26Smoke: Low | 74, above 70 ppb06/24/26Smoke: High | 66 | 79, above 75 ppb | 73, above 70 ppb |
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| Boulder Reservoir | 76, above 75 ppb07/13/26Smoke: Low | 75, above 70 ppb08/07/26Smoke: High | 74, above 70 ppb07/02/26Smoke: Low | 73, above 70 ppb08/06/26Smoke: High | 69 | 84, above 75 ppb | 75, above 70 ppb |
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| CAMP | 77, above 75 ppb07/06/26Smoke: Moderate | 73, above 70 ppb08/07/26Smoke: High | 71, above 70 ppb07/20/26Smoke: Low | 7007/31/26Smoke: Low | 69 | 79, above 75 ppb | 72, above 70 ppb |
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| La Casa | 80, above 75 ppb07/06/26Smoke: High | 76, above 75 ppb07/20/26Smoke: Low | 75, above 70 ppb08/07/26Smoke: High | 74, above 70 ppb07/14/26Smoke: Low | 71, above 70 ppb | 84, above 75 ppb | 76, above 75 ppb |
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| Chatfield | 83, above 75 ppb08/07/26Smoke: Moderate | 83, above 75 ppb06/29/26Smoke: High | 80, above 75 ppb06/20/26Smoke: None | 79, above 75 ppb08/05/26Smoke: High | 73, above 70 ppb | 88, above 75 ppb | 80, above 75 ppb |
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| Evergreen | 88, above 75 ppb08/07/26Smoke: Moderate | 86, above 75 ppb06/29/26Smoke: Low | 83, above 75 ppb08/06/26Smoke: High | 81, above 75 ppb06/18/26Smoke: None | 73, above 70 ppb | 85, above 75 ppb | 79, above 75 ppb |
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| Fossil Crk | 81, above 75 ppb07/06/26Smoke: High | 81, above 75 ppb07/13/26Smoke: Low | 79, above 75 ppb07/20/26Smoke: None | 79, above 75 ppb07/25/26Smoke: Low | 67 | 84, above 75 ppb | 76, above 75 ppb |
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| Fort Collins - CSU | 77, above 75 ppb07/13/26Smoke: Low | 76, above 75 ppb07/20/26Smoke: None | 74, above 70 ppb07/12/26Smoke: None | 73, above 70 ppb07/02/26Smoke: High | 67 | 82, above 75 ppb | 74, above 70 ppb |
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| Fort Collins West | 77, above 75 ppb07/13/26Smoke: Low | 76, above 75 ppb07/20/26Smoke: None | 74, above 70 ppb07/12/26Smoke: None | 74, above 70 ppb07/02/26Smoke: High | 72, above 70 ppb | 83, above 75 ppb | 76, above 75 ppb |
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| Greeley Weld County | 78, above 75 ppb07/06/26Smoke: Moderate | 77, above 75 ppb05/15/26Smoke: None | 76, above 75 ppb07/05/26Smoke: Moderate | 75, above 70 ppb07/24/26Smoke: Low | 71, above 70 ppb | 81, above 75 ppb | 75, above 70 ppb |
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| Highlands | 81, above 75 ppb06/29/26Smoke: High | 80, above 75 ppb06/20/26Smoke: None | 79, above 75 ppb08/07/26Smoke: Moderate | 77, above 75 ppb08/06/26Smoke: High | 60 | 73, above 70 ppb | 70 |
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| NREL | 97, above 75 ppb08/07/26Smoke: Moderate | 92, above 75 ppb07/13/26Smoke: Low | 86, above 75 ppb07/06/26Smoke: High | 85, above 75 ppb08/06/26Smoke: High | 71, above 70 ppb | 86, above 75 ppb | 80, above 75 ppb |
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| *^Mehaffey Park | 78, above 75 ppb07/13/26Smoke: Low | 77, above 75 ppb07/20/26Smoke: None | 77, above 75 ppb07/06/26Smoke: High | 75, above 70 ppb07/24/26Smoke: Low | 70 | NA | NA |
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| **LaSalle Tower | 77, above 75 ppb07/06/26Smoke: High | 75, above 70 ppb05/15/26Smoke: None | 74, above 70 ppb07/05/26Smoke: Moderate | 74, above 70 ppb05/11/26Smoke: None | 69 | 79, above 75 ppb | 72, above 70 ppb |
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| Rocky Flats North | 91, above 75 ppb08/07/26Smoke: High | 90, above 75 ppb07/06/26Smoke: High | 86, above 75 ppb07/13/26Smoke: Low | 84, above 75 ppb07/20/26Smoke: None | 72, above 70 ppb | 88, above 75 ppb | 81, above 75 ppb |
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| *^Timnath | 82, above 75 ppb07/06/26Smoke: High | 76, above 75 ppb07/25/26Smoke: Low | 76, above 75 ppb07/20/26Smoke: None | 76, above 75 ppb07/13/26Smoke: Low | 73, above 70 ppb | 78, above 75 ppb | 75, above 70 ppb |
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| Welby | 83, above 75 ppb07/06/26Smoke: High | 80, above 75 ppb07/20/26Smoke: None | 78, above 75 ppb08/07/26Smoke: High | 76, above 75 ppb08/12/26Smoke: Moderate | 69 | 83, above 75 ppb | 76, above 75 ppb |
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Notes
- *Based on 8-hour averages of raw 1-hour ozone data from the Colorado Department of Public Health and Environment (CDPHE) and consistent with Data Reporting and Handling Conventions outlined in 40 CFR Part 50 - Appendix P.
- **The Platteville Observatory was brought offline 2/8/24 and replaced by the La Salle Tower monitor on 2/14/24
- ***The Aurora East Monitor went offline 7/28/2026
- *^Mehaffey Park was brought online 6/5/2025
- The form of the standard is in parts per million (ppm), however, values in this table are expressed in parts per billion (ppb) for simplicity.
- Data is synced monthly with Air Pollution Control Division (APCD) monthly ozone summary with final quality assurance conducted by APCD at end of ozone season.
- ^The 2024-2026 value is an estimate based on certified monitor data from 2024 and 2025 and uncertified current data from 2026 and is the average of the 4th highest monitored data by site over 2024-2026.
- ^^The smoke impact probability comes from the Smoke Impact Assessment System v2 prepared for the RAQC. It is designed to determine the retrospective probability that smoke is impacting ozone formation at each monitor in the non-attainment area. Observational data and modeling results are used to determine a probability of smoke impact at each site, either none, low, moderate or high. The full report describing this project is the Smoke Impact Assessment System (SIMAS) version 2 report.
Data summary provided by the Regional Air Quality Council (RAQC), 9/14/2026
Download the original summary table (image)Download the summary table from the RAQC file library
Number of Exceedances of the Levels of the Ozone Standards in the Denver Metro/North Front Range Nonattainment Area, 1995 to Present
- 71–75 ppb
- Above 75 ppb
Show the numbers
| Year | Days 71–75 ppb | Days above 75 ppb | Total days above 70 ppb |
|---|---|---|---|
| 2026 | 24 | 42 | 66 |
| 2025 | 17 | 6 | 23 |
| 2024 | 19 | 22 | 41 |
| 2023 | 17 | 10 | 27 |
| 2022 | 18 | 17 | 35 |
| 2021 | 19 | 48 | 67 |
| 2020 | 10 | 19 | 29 |
| 2019 | 15 | 7 | 22 |
| 2018 | 23 | 25 | 48 |
| 2017 | 23 | 13 | 36 |
| 2016 | 13 | 12 | 25 |
| 2015 | 10 | 17 | 27 |
| 2014 | 18 | 10 | 28 |
| 2013 | 25 | 19 | 44 |
| 2012 | 33 | 33 | 66 |
| 2011 | 19 | 29 | 48 |
| 2010 | 21 | 16 | 37 |
| 2009 | 10 | 8 | 18 |
| 2008 | 23 | 19 | 42 |
| 2007 | 29 | 24 | 53 |
| 2006 | 29 | 34 | 63 |
| 2005 | 18 | 22 | 40 |
| 2004 | 15 | 9 | 24 |
| 2003 | 21 | 41 | 62 |
| 2002 | 20 | 38 | 58 |
| 2001 | 15 | 13 | 28 |
| 2000 | 25 | 25 | 50 |
| 1999 | 14 | 15 | 29 |
| 1998 | 16 | 28 | 44 |
| 1997 | 15 | 9 | 24 |
| 1996 | 30 | 18 | 48 |
| 1995 | 15 | 14 | 29 |
About the data
8-hour Ozone Summary is based on 8-hour averages of raw 1-hour ozone data from the Colorado Department of Public Health and Environment (CDPHE) through EPA AirNow and consistent with Data Reporting and Handling Conventions outlined in 40 CFR Part 50 – Appendix P.
Donate to the RAQC Clean Air Fund
The RAQC Clean Air Fund, a 501(c)(3) public charity, is dedicated to funding and supplementing RAQC air quality programs that reduce Ozone within the EPA’s Denver Metro/Front Range Ozone Non-Attainment Area.