Rochester Air Quality in December
Across 2019–2025, Rochester's December air quality had a median AQI of 47 (Good) over 217 monitored days in the Rochester, NY 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 84.8% of days. The cleanest December on record here was 2025 (median AQI 34, 0 days above 100) and the worst was 2022 (median 52, 0 days above 100, peak AQI 65).
- Good: 55.8%
- Moderate: 44.2%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Rochester in December?
Good on a typical day: median AQI 47 across 2019–2025, with 0.0% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓55.8% of December days were Good (AQI 0–50), 44.2% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the December peak was 81.
- ✓Best December: 2025; worst December: 2022.
Frequently asked questions
What is the air quality like in Rochester in December?▾
Across 2019–2025, the median daily AQI in Rochester in December was 47 (Good). 55.8% of days were Good, 44.2% 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 Rochester?▾
A typical December day in Rochester sits in the Good range (median AQI 47), 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 Rochester's December air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 84.8% of December days in Rochester. The highest December AQI recorded in 2019–2025 was 81 (Moderate), in 2022.
Rochester December air quality, year by year
Rochester December air quality by year (Rochester, NY, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 46 | 0 | 69 | PM2.5 |
| 2020 | 31 | 52 | 0 | 81 | PM2.5 |
| 2021 | 31 | 52 | 0 | 64 | PM2.5 |
| 2022worst | 31 | 52 | 0 | 65 | PM2.5 |
| 2023 | 31 | 38 | 0 | 67 | PM2.5 |
| 2024 | 31 | 42 | 0 | 66 | PM2.5 |
| 2025cleanest | 31 | 34 | 0 | 66 | PM2.5 |
What December air means in Rochester
A typical December day in Rochester sits in the Good range (median AQI 47), 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 47 is above Rochester's whole-year median of 42, 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 Rochester 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 Rochester's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Rochester, NY), 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.