Aurora, IL Air Quality in January

Across 2019–2025, Aurora's January air quality had a median AQI of 57 (Moderate) over 217 monitored days in the Chicago-Naperville-Elgin, IL-IN-WI 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 95.4% of days. The cleanest January on record here was 2025 (median AQI 54, 0 days above 100) and the worst was 2021 (median 61, 0 days above 100, peak AQI 87).

57
Median AQI
Moderate
0.0%
Days above AQI 100
0 of 217 days
71
90th percentile AQI
worst 1 day in 10
96
Peak AQI
Moderate
PM2.5
Main pollutant
95.4% of days
18.9%
Good days
41 of 217
  • Good: 18.9%
  • Moderate: 81.1%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Aurora in January?

Moderate on a typical day: median AQI 57 across 2019–2025, with 0.0% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 18.9% of January days were Good (AQI 0–50), 81.1% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the January peak was 96.
  • Best January: 2025; worst January: 2021.

Frequently asked questions

What is the air quality like in Aurora in January?

Across 2019–2025, the median daily AQI in Aurora in January was 57 (Moderate). 18.9% of days were Good, 81.1% 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 Aurora?

A typical January day in Aurora is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of January days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Aurora's January air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 95.4% of January days in Aurora. The highest January AQI recorded in 2019–2025 was 96 (Moderate), in 2021.

Aurora January air quality, year by year

Aurora January air quality by year (Chicago-Naperville-Elgin, IL-IN-WI, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193158074PM2.5
20203158080PM2.5
2021worst3161087PM2.5
20223157096PM2.5
20233158084PM2.5
20243156081PM2.5
2025cleanest3154079PM2.5

What January air means in Aurora

A typical January day in Aurora is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of January days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

January's median AQI of 57 is in line with Aurora's whole-year median of 60, 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 Aurora 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 Aurora's winter season (December, January, February); the winter page pools all three months.

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

Right now in Aurora

The latest EPA AirNow observation puts Aurora's AQI at 39 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Aurora air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Chicago-Naperville-Elgin, IL-IN-WI), 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.