Peoria Air Quality in January

Across 2019–2025, Peoria's January air quality had a median AQI of 47 (Good) over 182 monitored days in the Peoria, IL area. 0.0% of January days (0 of 182) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 100.0% of days. The cleanest January on record here was 2025 (median AQI 37, 0 days above 100) and the worst was 2023 (median 52, 0 days above 100, peak AQI 76).

47
Median AQI
Good
0.0%
Days above AQI 100
0 of 182 days
62
90th percentile AQI
worst 1 day in 10
85
Peak AQI
Moderate
PM2.5
Main pollutant
100.0% of days
57.7%
Good days
105 of 182
  • Good: 57.7%
  • Moderate: 42.3%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Peoria in January?

Good on a typical day: median AQI 47 across 2019–2025, with 0.0% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 57.7% of January days were Good (AQI 0–50), 42.3% Moderate (51–100).
  • 0 days of 182 reached AQI 101+; the January peak was 85.
  • Best January: 2025; worst January: 2023.

Frequently asked questions

What is the air quality like in Peoria in January?

Across 2019–2025, the median daily AQI in Peoria in January was 47 (Good). 57.7% of days were Good, 42.3% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 182 monitored days in EPA's Air Quality System.

Is January a good time for outdoor exercise in Peoria?

A typical January day in Peoria sits in the Good range (median AQI 47), 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 Peoria's January air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 100.0% of January days in Peoria. The highest January AQI recorded in 2019–2025 was 85 (Moderate), in 2023.

Peoria January air quality, year by year

Peoria January air quality by year (Peoria, IL, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193148071PM2.5
20203146071PM2.5
20212749067PM2.5
20223152085PM2.5
2023worst2252076PM2.5
2024941053PM2.5
2025cleanest3137066PM2.5

What January air means in Peoria

A typical January day in Peoria sits in the Good range (median AQI 47), 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 47 is in line with Peoria's whole-year median of 45, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median January AQI across every EPA metro area (95,602 metro-days, 2019–2025) is 39, so Peoria runs above the national January norm; 0.0% of its January days topped AQI 100 versus 0.7% nationally (about the same).

January is part of Peoria's winter season (December, January, February); the winter page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Peoria

The latest EPA AirNow observation puts Peoria's AQI at 42 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Peoria air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Peoria, IL), 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.