Billings Air Quality in April

Across 2019–2025, Billings's April air quality had a median AQI of 33 (Good) over 183 monitored days in the Billings, MT area. 0.0% of April days (0 of 183) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 68.3% of days. The cleanest April on record here was 2022 (median AQI 22, 0 days above 100) and the worst was 2024 (median 43, 0 days above 100, peak AQI 64).

33
Median AQI
Good
0.0%
Days above AQI 100
0 of 183 days
45
90th percentile AQI
worst 1 day in 10
68
Peak AQI
Moderate
PM2.5
Main pollutant
68.3% of days
96.2%
Good days
176 of 183
  • Good: 96.2%
  • Moderate: 3.8%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Billings in April?

Good on a typical day: median AQI 33 across 2019–2025, with 0.0% of April days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 96.2% of April days were Good (AQI 0–50), 3.8% Moderate (51–100).
  • 0 days of 183 reached AQI 101+; the April peak was 68.
  • Best April: 2022; worst April: 2024.

Frequently asked questions

What is the air quality like in Billings in April?

Across 2019–2025, the median daily AQI in Billings in April was 33 (Good). 96.2% of days were Good, 3.8% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 183 monitored days in EPA's Air Quality System.

Is April a good time for outdoor exercise in Billings?

A typical April day in Billings sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.

Which pollutant causes Billings's April air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 68.3% of April days in Billings. The highest April AQI recorded in 2019–2025 was 68 (Moderate), in 2024.

Billings April air quality, year by year

Billings April air quality by year (Billings, MT, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
2019820045PM2.5
20203031052PM2.5
20212629048PM2.5
2022cleanest3022042PM2.5
20232924068PM2.5
2024worst3043064O3
20253040054O3

What April air means in Billings

A typical April day in Billings sits in the Good range (median AQI 33), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.

April's median AQI of 33 is below Billings's whole-year median of 38, making it one of the area's cleaner periods. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Billings runs below the national April norm; 0.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).

April is part of Billings's spring season (March, April, May); the spring 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.