Peoria Air Quality in December
Across 2019–2025, Peoria's December air quality had a median AQI of 49 (Good) over 181 monitored days in the Peoria, IL area. 0.0% of December days (0 of 181) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 100.0% of days. The cleanest December on record here was 2023 (median AQI 38, 0 days above 100) and the worst was 2021 (median 57, 0 days above 100, peak AQI 71).
- Good: 51.4%
- Moderate: 48.6%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Peoria in December?
Good on a typical day: median AQI 49 across 2019–2025, with 0.0% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓51.4% of December days were Good (AQI 0–50), 48.6% Moderate (51–100).
- ✓0 days of 181 reached AQI 101+; the December peak was 89.
- ✓Best December: 2023; worst December: 2021.
Frequently asked questions
What is the air quality like in Peoria in December?▾
Across 2019–2025, the median daily AQI in Peoria in December was 49 (Good). 51.4% of days were Good, 48.6% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 181 monitored days in EPA's Air Quality System.
Is December a good time for outdoor exercise in Peoria?▾
A typical December day in Peoria sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
Which pollutant causes Peoria's December air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 100.0% of December days in Peoria. The highest December AQI recorded in 2019–2025 was 89 (Moderate), in 2021.
Peoria December air quality, year by year
Peoria December air quality by year (Peoria, IL, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 54 | 0 | 71 | PM2.5 |
| 2020 | 31 | 56 | 0 | 89 | PM2.5 |
| 2021worst | 31 | 57 | 0 | 71 | PM2.5 |
| 2023cleanest | 31 | 38 | 0 | 58 | PM2.5 |
| 2024 | 31 | 44 | 0 | 70 | PM2.5 |
| 2025 | 26 | 41 | 0 | 85 | PM2.5 |
What December air means in Peoria
A typical December day in Peoria sits in the Good range (median AQI 49), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
December's median AQI of 49 is above Peoria's whole-year median of 45, making it one of the area's dirtier periods. Nationally, the median December AQI across every EPA metro area (95,590 metro-days, 2019–2025) is 39, so Peoria runs above the national December norm; 0.0% of its December days topped AQI 100 versus 0.7% nationally (about the same).
December 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.