Winston-Salem Air Quality in December

Across 2019–2025, Winston-Salem's December air quality had a median AQI of 54 (Moderate) over 217 monitored days in the Winston-Salem, NC area. 0.0% of December days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 98.6% of days. The cleanest December on record here was 2023 (median AQI 49, 0 days above 100) and the worst was 2022 (median 57, 0 days above 100, peak AQI 75).

54
Median AQI
Moderate
0.0%
Days above AQI 100
0 of 217 days
67
90th percentile AQI
worst 1 day in 10
92
Peak AQI
Moderate
PM2.5
Main pollutant
98.6% of days
40.1%
Good days
87 of 217
  • Good: 40.1%
  • Moderate: 59.9%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Winston-Salem in December?

Moderate on a typical day: median AQI 54 across 2019–2025, with 0.0% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 40.1% of December days were Good (AQI 0–50), 59.9% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the December peak was 92.
  • Best December: 2023; worst December: 2022.

Frequently asked questions

What is the air quality like in Winston-Salem in December?

Across 2019–2025, the median daily AQI in Winston-Salem in December was 54 (Moderate). 40.1% of days were Good, 59.9% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is December a good time for outdoor exercise in Winston-Salem?

A typical December day in Winston-Salem is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of December 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 Winston-Salem's December air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 98.6% of December days in Winston-Salem. The highest December AQI recorded in 2019–2025 was 92 (Moderate), in 2022.

Winston-Salem December air quality, year by year

Winston-Salem December air quality by year (Winston-Salem, NC, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193151092PM2.5
20203155088PM2.5
20213152066PM2.5
2022worst3157075PM2.5
2023cleanest3149092PM2.5
20243154073PM2.5
20253156078PM2.5

What December air means in Winston-Salem

A typical December day in Winston-Salem is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of December days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

December's median AQI of 54 is above Winston-Salem's whole-year median of 50, 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 Winston-Salem 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 Winston-Salem's winter season (December, January, February); the winter page pools all three months.

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

Right now in Winston-Salem

The latest EPA AirNow observation puts Winston-Salem's AQI at 52 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Winston-Salem air quality →

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