Cheyenne Air Quality in January
Across 2019–2025, Cheyenne's January air quality had a median AQI of 38 (Good) over 217 monitored days in the Cheyenne, WY area. 0.0% of January days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 89.4% of days. The cleanest January on record here was 2019 (median AQI 37, 0 days above 100) and the worst was 2025 (median 42, 0 days above 100, peak AQI 51).
- Good: 96.8%
- Moderate: 3.2%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Cheyenne
Today's main pollutant in Cheyenne is ground-level ozone (AQI 31). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Cheyenne in January?
Good on a typical day: median AQI 38 across 2019–2025, with 0.0% of January days above AQI 100. Ground-level ozone is the main driver.
- ✓96.8% of January days were Good (AQI 0–50), 3.2% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the January peak was 58.
- ✓Best January: 2019; worst January: 2025.
Frequently asked questions
What is the air quality like in Cheyenne in January?▾
Across 2019–2025, the median daily AQI in Cheyenne in January was 38 (Good). 96.8% of days were Good, 3.2% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is January a good time for outdoor exercise in Cheyenne?▾
A typical January day in Cheyenne sits in the Good range (median AQI 38), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of January days reached AQI 101+ in 2019–2025.
Which pollutant causes Cheyenne's January air quality problems?▾
Ground-level ozone set the daily AQI on 89.4% of January days in Cheyenne. The highest January AQI recorded in 2019–2025 was 58 (Moderate), in 2025.
Cheyenne January air quality, year by year
Cheyenne January air quality by year (Cheyenne, WY, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 37 | 0 | 43 | O3 |
| 2020 | 31 | 38 | 0 | 52 | O3 |
| 2021 | 31 | 38 | 0 | 42 | O3 |
| 2022 | 31 | 41 | 0 | 44 | O3 |
| 2023 | 31 | 37 | 0 | 46 | O3 |
| 2024 | 31 | 41 | 0 | 58 | O3 |
| 2025worst | 31 | 42 | 0 | 51 | O3 |
What January air means in Cheyenne
A typical January day in Cheyenne sits in the Good range (median AQI 38), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of January days reached AQI 101+ in 2019–2025.
January's median AQI of 38 is below Cheyenne's whole-year median of 44, making it one of the area's cleaner periods. Nationally, the median January AQI across every EPA metro area (95,602 metro-days, 2019–2025) is 39, so Cheyenne runs in line with the national January norm; 0.0% of its January days topped AQI 100 versus 0.7% nationally (about the same).
January is part of Cheyenne's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Cheyenne
The latest EPA AirNow observation puts Cheyenne's AQI at 31 (O3). The figures above are multi-year month statistics, not today's reading.
View current Cheyenne air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Cheyenne, WY), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.