Billings Air Quality in January
Across 2019–2025, Billings's January air quality had a median AQI of 31 (Good) over 217 monitored days in the Billings, MT area. 0.0% of January days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 88.9% of days. The cleanest January on record here was 2021 (median AQI 28, 0 days above 100) and the worst was 2019 (median 34, 0 days above 100, peak AQI 56).
- Good: 82.9%
- Moderate: 17.1%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Billings in January?
Good on a typical day: median AQI 31 across 2019–2025, with 0.0% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓82.9% of January days were Good (AQI 0–50), 17.1% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the January peak was 71.
- ✓Best January: 2021; worst January: 2019.
Frequently asked questions
What is the air quality like in Billings in January?▾
Across 2019–2025, the median daily AQI in Billings in January was 31 (Good). 82.9% of days were Good, 17.1% 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 Billings?▾
A typical January day in Billings sits in the Good range (median AQI 31), 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 Billings's January air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 88.9% of January days in Billings. The highest January AQI recorded in 2019–2025 was 71 (Moderate), in 2019.
Billings January air quality, year by year
Billings January air quality by year (Billings, MT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 31 | 34 | 0 | 56 | PM2.5 |
| 2020 | 31 | 32 | 0 | 70 | PM2.5 |
| 2021cleanest | 31 | 28 | 0 | 71 | PM2.5 |
| 2022 | 31 | 31 | 0 | 59 | PM2.5 |
| 2023 | 31 | 28 | 0 | 55 | PM2.5 |
| 2024 | 31 | 33 | 0 | 58 | PM2.5 |
| 2025 | 31 | 28 | 0 | 55 | PM2.5 |
What January air means in Billings
A typical January day in Billings sits in the Good range (median AQI 31), 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 31 is below Billings's whole-year median of 38, 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 Billings runs below the national January norm; 0.0% of its January days topped AQI 100 versus 0.7% nationally (about the same).
January is part of Billings's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Billings
The latest EPA AirNow observation puts Billings's AQI at 21 (O3). The figures above are multi-year month statistics, not today's reading.
View current Billings air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Billings, MT), 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.