Madison Air Quality in January
Across 2019–2025, Madison's January air quality had a median AQI of 48 (Good) over 217 monitored days in the Madison, 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 100.0% of days. The cleanest January on record here was 2025 (median AQI 32, 0 days above 100) and the worst was 2021 (median 55, 0 days above 100, peak AQI 81).
- Good: 55.3%
- Moderate: 44.7%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Madison in January?
Good on a typical day: median AQI 48 across 2019–2025, with 0.0% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓55.3% of January days were Good (AQI 0–50), 44.7% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the January peak was 88.
- ✓Best January: 2025; worst January: 2021.
Frequently asked questions
What is the air quality like in Madison in January?▾
Across 2019–2025, the median daily AQI in Madison in January was 48 (Good). 55.3% of days were Good, 44.7% 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 Madison?▾
A typical January day in Madison sits in the Good range (median AQI 48), 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 Madison's January air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 100.0% of January days in Madison. The highest January AQI recorded in 2019–2025 was 88 (Moderate), in 2021.
Madison January air quality, year by year
Madison January air quality by year (Madison, WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 51 | 0 | 69 | PM2.5 |
| 2020 | 31 | 51 | 0 | 78 | PM2.5 |
| 2021worst | 31 | 55 | 0 | 81 | PM2.5 |
| 2022 | 31 | 49 | 0 | 81 | PM2.5 |
| 2023 | 31 | 52 | 0 | 88 | PM2.5 |
| 2024 | 31 | 40 | 0 | 74 | PM2.5 |
| 2025cleanest | 31 | 32 | 0 | 66 | PM2.5 |
What January air means in Madison
A typical January day in Madison sits in the Good range (median AQI 48), 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 48 is in line with Madison'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 Madison 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 Madison's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Madison
The latest EPA AirNow observation puts Madison's AQI at 49 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Madison air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Madison, 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.