Billings Air Quality in July
Across 2019–2025, Billings's July air quality had a median AQI of 42 (Good) over 215 monitored days in the Billings, MT area. 4.7% of July days (10 of 215) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 80.0% of days. The cleanest July on record here was 2025 (median AQI 42, 0 days above 100) and the worst was 2021 (median 69, 4 days above 100, peak AQI 128).
- Good: 62.3%
- Moderate: 33.0%
- Unhealthy for Sensitive Groups: 3.3%
- Unhealthy or worse: 1.4%
Reduce Indoor Ozone in Billings
Today's main pollutant in Billings is ground-level ozone (AQI 21). 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 Billings in July?
Good on a typical day: median AQI 42 across 2019–2025, with 4.7% of July days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓62.3% of July days were Good (AQI 0–50), 33.0% Moderate (51–100).
- ✓10 days of 215 reached AQI 101+; the July peak was 163.
- ✓Best July: 2025; worst July: 2021.
Frequently asked questions
What is the air quality like in Billings in July?▾
Across 2019–2025, the median daily AQI in Billings in July was 42 (Good). 62.3% of days were Good, 33.0% Moderate, and 4.7% reached Unhealthy for Sensitive Groups or worse, based on 215 monitored days in EPA's Air Quality System.
Is July a good time for outdoor exercise in Billings?▾
A typical July day in Billings sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 21 of July days (4.7%) reached AQI 101+ in 2019–2025.
Which pollutant causes Billings's July air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 80.0% of July days in Billings. The highest July AQI recorded in 2019–2025 was 163 (Unhealthy), in 2021.
Billings July air quality, year by year
Billings July air quality by year (Billings, MT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 29 | 32 | 1 | 159 | PM2.5 |
| 2020 | 31 | 30 | 1 | 163 | PM2.5 |
| 2021worst | 31 | 69 | 4 | 128 | PM2.5 |
| 2022 | 31 | 35 | 1 | 155 | PM2.5 |
| 2023 | 31 | 32 | 2 | 115 | PM2.5 |
| 2024 | 31 | 61 | 1 | 105 | O3 |
| 2025cleanest | 31 | 42 | 0 | 88 | O3 |
What July air means in Billings
A typical July day in Billings sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 21 of July days (4.7%) reached AQI 101+ in 2019–2025.
July's median AQI of 42 is above Billings's whole-year median of 38, making it one of the area's dirtier periods. Nationally, the median July AQI across every EPA metro area (103,858 metro-days, 2019–2025) is 47, so Billings runs below the national July norm; 4.7% of its July days topped AQI 100 versus 3.6% nationally (above average).
July is part of Billings's summer season (June, July, August); the summer 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.