Hartford Air Quality in Spring
Across 2019–2025, Hartford's spring (March–May) air quality had a median AQI of 44 (Good) over 644 monitored days in the Hartford-West Hartford-East Hartford, CT area. 1.0% of spring days (6 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 81.2% of days. The cleanest spring on record here was 2020 (median AQI 41, 0 days above 100) and the worst was 2023 (median 46, 2 days above 100, peak AQI 156).
- Good: 78.3%
- Moderate: 20.8%
- Unhealthy for Sensitive Groups: 0.8%
- Unhealthy or worse: 0.2%
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How is the air in Hartford in spring?
Good on a typical day: median AQI 44 across 2019–2025, with 1.0% of spring days above AQI 100. Ground-level ozone is the main driver.
- ✓78.3% of spring days were Good (AQI 0–50), 20.8% Moderate (51–100).
- ✓6 days of 644 reached AQI 101+; the spring peak was 156.
- ✓Cleanest month: March; worst month: April.
Frequently asked questions
What is the air quality like in Hartford in spring?▾
Across 2019–2025, the median daily AQI in Hartford in spring was 44 (Good). 78.3% of days were Good, 20.8% Moderate, and 1.0% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Hartford?▾
A typical spring day in Hartford sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 100 of spring days (1.0%) reached AQI 101+ in 2019–2025.
Which pollutant causes Hartford's spring air quality problems?▾
Ground-level ozone set the daily AQI on 81.2% of spring days in Hartford. The highest spring AQI recorded in 2019–2025 was 156 (Unhealthy), in 2023.
Hartford spring air quality, year by year
Hartford spring 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 | 92 | 45 | 0 | 78 | O3 |
| 2020cleanest | 92 | 41 | 0 | 84 | O3 |
| 2021 | 92 | 43 | 1 | 101 | O3 |
| 2022 | 92 | 43 | 0 | 87 | O3 |
| 2023worst | 92 | 46 | 2 | 156 | O3 |
| 2024 | 92 | 40 | 1 | 119 | O3 |
| 2025 | 92 | 45 | 2 | 101 | O3 |
What spring air means in Hartford
A typical spring day in Hartford sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 100 of spring days (1.0%) reached AQI 101+ in 2019–2025.
Spring's median AQI of 44 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 Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Hartford runs in line with the national Spring norm; 1.0% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, March is the cleanest month (median AQI 43, 0.0% of days above 100) and April the worst (median 44, 1.5% 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.