New Haven Air Quality in January
Across 2019–2025, New Haven's January air quality had a median AQI of 41 (Good) over 217 monitored days in the New Haven-Milford, CT 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 71.9% of days. The cleanest January on record here was 2023 (median AQI 37, 0 days above 100) and the worst was 2022 (median 53, 0 days above 100, peak AQI 81).
- Good: 63.1%
- Moderate: 36.9%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in New Haven in January?
Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓63.1% of January days were Good (AQI 0–50), 36.9% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the January peak was 95.
- ✓Best January: 2023; worst January: 2022.
Frequently asked questions
What is the air quality like in New Haven in January?▾
Across 2019–2025, the median daily AQI in New Haven in January was 41 (Good). 63.1% of days were Good, 36.9% 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 New Haven?▾
A typical January day in New Haven sits in the Good range (median AQI 41), 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 New Haven's January air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 71.9% of January days in New Haven. The highest January AQI recorded in 2019–2025 was 95 (Moderate), in 2022.
New Haven January air quality, year by year
New Haven January air quality by year (New Haven-Milford, CT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 40 | 0 | 65 | PM2.5 |
| 2020 | 31 | 48 | 0 | 85 | PM2.5 |
| 2021 | 31 | 42 | 0 | 95 | PM2.5 |
| 2022worst | 31 | 53 | 0 | 81 | PM2.5 |
| 2023cleanest | 31 | 37 | 0 | 66 | PM2.5 |
| 2024 | 31 | 37 | 0 | 63 | PM2.5 |
| 2025 | 31 | 37 | 0 | 69 | O3 |
What January air means in New Haven
A typical January day in New Haven sits in the Good range (median AQI 41), 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 41 is in line with New Haven's whole-year median of 44, 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 New Haven runs in line with the national January norm; 0.0% of its January days topped AQI 100 versus 0.7% nationally (about the same).
January is part of New Haven's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in New Haven
The latest EPA AirNow observation puts New Haven's AQI at 32 (O3). The figures above are multi-year month statistics, not today's reading.
View current New Haven air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (New Haven-Milford, CT), 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.