Hartford Air Quality in Winter
Across 2019–2025, Hartford's winter (December–February) air quality had a median AQI of 41 (Good) over 632 monitored days in the Hartford-West Hartford-East Hartford, CT area. 0.0% of winter days (0 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 63.8% of days. The cleanest winter on record here was 2024 (median AQI 38, 0 days above 100) and the worst was 2021 (median 45, 0 days above 100, peak AQI 93).
- Good: 63.0%
- Moderate: 37.0%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Improve Indoor Air Quality
Even with good outdoor air in Hartford, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
Recommended: Levoit Core 400S — True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Hartford in winter?
Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓63.0% of winter days were Good (AQI 0–50), 37.0% Moderate (51–100).
- ✓0 days of 632 reached AQI 101+; the winter peak was 98.
- ✓Cleanest month: January; worst month: February.
Frequently asked questions
What is the air quality like in Hartford in winter?▾
Across 2019–2025, the median daily AQI in Hartford in winter was 41 (Good). 63.0% of days were Good, 37.0% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Hartford?▾
A typical winter day in Hartford 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 winter days reached AQI 101+ in 2019–2025.
Which pollutant causes Hartford's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 63.8% of winter days in Hartford. The highest winter AQI recorded in 2019–2025 was 98 (Moderate), in 2021.
Hartford winter air quality, year by year
Hartford winter air quality by year (Hartford-West Hartford-East Hartford, CT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 43 | 0 | 92 | PM2.5 |
| 2020 | 91 | 45 | 0 | 98 | PM2.5 |
| 2021worst | 90 | 45 | 0 | 93 | PM2.5 |
| 2022 | 90 | 41 | 0 | 80 | PM2.5 |
| 2023 | 90 | 39 | 0 | 79 | PM2.5 |
| 2024cleanest | 91 | 38 | 0 | 75 | PM2.5 |
| 2025 | 90 | 40 | 0 | 75 | PM2.5 |
What winter air means in Hartford
A typical winter day in Hartford 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 winter days reached AQI 101+ in 2019–2025.
Winter's median AQI of 41 is in line with Hartford's whole-year median of 43, 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 Hartford 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 39, 0.0% of days above 100) and February the worst (median 42, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Hartford
The latest EPA AirNow observation puts Hartford's AQI at 36 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Hartford air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Hartford-West Hartford-East Hartford, 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.