Hartford Air Quality in August

Across 2019–2025, Hartford's August air quality had a median AQI of 48 (Good) over 217 monitored days in the Hartford-West Hartford-East Hartford, CT area. 5.1% of August days (11 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 59.0% of days. The cleanest August on record here was 2023 (median AQI 44, 0 days above 100) and the worst was 2025 (median 50, 3 days above 100, peak AQI 164).

48
Median AQI
Good
5.1%
Days above AQI 100
11 of 217 days
85
90th percentile AQI
worst 1 day in 10
164
Peak AQI
Unhealthy
O3
Main pollutant
59.0% of days
56.2%
Good days
122 of 217
  • Good: 56.2%
  • Moderate: 38.7%
  • Unhealthy for Sensitive Groups: 4.6%
  • Unhealthy or worse: 0.5%

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QUICK ANSWER

How is the air in Hartford in August?

Good on a typical day: median AQI 48 across 2019–2025, with 5.1% of August days above AQI 100. Ground-level ozone is the main driver.

  • 56.2% of August days were Good (AQI 0–50), 38.7% Moderate (51–100).
  • 11 days of 217 reached AQI 101+; the August peak was 164.
  • Best August: 2023; worst August: 2025.

Frequently asked questions

What is the air quality like in Hartford in August?

Across 2019–2025, the median daily AQI in Hartford in August was 48 (Good). 56.2% of days were Good, 38.7% Moderate, and 5.1% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is August a good time for outdoor exercise in Hartford?

A typical August day in Hartford sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 20 of August days (5.1%) reached AQI 101+ in 2019–2025.

Which pollutant causes Hartford's August air quality problems?

Ground-level ozone set the daily AQI on 59.0% of August days in Hartford. The highest August AQI recorded in 2019–2025 was 164 (Unhealthy), in 2025.

Hartford August air quality, year by year

Hartford August air quality by year (Hartford-West Hartford-East Hartford, CT, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931491119O3
202031511101O3
202131493129O3
202231463147O3
2023cleanest3144065PM2.5
20243146081O3
2025worst31503164O3

What August air means in Hartford

A typical August day in Hartford sits in the Good range (median AQI 48), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 20 of August days (5.1%) reached AQI 101+ in 2019–2025.

August's median AQI of 48 is above Hartford's whole-year median of 43, making it one of the area's dirtier periods. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Hartford runs in line with the national August norm; 5.1% of its August days topped AQI 100 versus 3.5% nationally (above average).

August is part of Hartford's summer season (June, July, August); the summer page pools all three months.

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 month 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.