Durham Air Quality in Winter
Across 2019–2025, Durham's winter (December–February) air quality had a median AQI of 43 (Good) over 627 monitored days in the Durham-Chapel Hill, NC area. 0.0% of winter days (0 of 627) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 98.4% of days. The cleanest winter on record here was 2020 (median AQI 31, 0 days above 100) and the worst was 2024 (median 55, 0 days above 100, peak AQI 80).
- Good: 63.3%
- Moderate: 36.7%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Durham in winter?
Good on a typical day: median AQI 43 across 2019–2025, with 0.0% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓63.3% of winter days were Good (AQI 0–50), 36.7% Moderate (51–100).
- ✓0 days of 627 reached AQI 101+; the winter peak was 92.
- ✓Cleanest month: January; worst month: December.
Frequently asked questions
What is the air quality like in Durham in winter?▾
Across 2019–2025, the median daily AQI in Durham in winter was 43 (Good). 63.3% of days were Good, 36.7% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 627 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Durham?▾
A typical winter day in Durham sits in the Good range (median AQI 43), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Which pollutant causes Durham's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 98.4% of winter days in Durham. The highest winter AQI recorded in 2019–2025 was 92 (Moderate), in 2024.
Durham winter air quality, year by year
Durham winter air quality by year (Durham-Chapel Hill, NC, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 52 | 0 | 74 | PM2.5 |
| 2020cleanest | 90 | 31 | 0 | 92 | PM2.5 |
| 2021 | 90 | 43 | 0 | 69 | PM2.5 |
| 2022 | 90 | 38 | 0 | 66 | PM2.5 |
| 2023 | 86 | 37 | 0 | 73 | PM2.5 |
| 2024worst | 91 | 55 | 0 | 80 | PM2.5 |
| 2025 | 90 | 40 | 0 | 65 | PM2.5 |
What winter air means in Durham
A typical winter day in Durham sits in the Good range (median AQI 43), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Winter's median AQI of 43 is in line with Durham's whole-year median of 44, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Durham runs in line with the national Winter norm; 0.0% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, January is the cleanest month (median AQI 42, 0.0% of days above 100) and December the worst (median 46, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Durham
The latest EPA AirNow observation puts Durham's AQI at 41 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Durham air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Durham-Chapel Hill, NC), 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.