Manchester Air Quality in October
Across 2019–2025, Manchester's October air quality had a median AQI of 31 (Good) over 217 monitored days in the Manchester-Nashua, NH area. 0.0% of October days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 94.9% of days. The cleanest October on record here was 2021 (median AQI 27, 0 days above 100) and the worst was 2022 (median 36, 0 days above 100, peak AQI 61).
- Good: 95.4%
- Moderate: 4.6%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Manchester in October?
Good on a typical day: median AQI 31 across 2019–2025, with 0.0% of October days above AQI 100. Ground-level ozone is the main driver.
- ✓95.4% of October days were Good (AQI 0–50), 4.6% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the October peak was 100.
- ✓Best October: 2021; worst October: 2022.
Frequently asked questions
What is the air quality like in Manchester in October?▾
Across 2019–2025, the median daily AQI in Manchester in October was 31 (Good). 95.4% of days were Good, 4.6% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Manchester?▾
A typical October day in Manchester sits in the Good range (median AQI 31), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
Which pollutant causes Manchester's October air quality problems?▾
Ground-level ozone set the daily AQI on 94.9% of October days in Manchester. The highest October AQI recorded in 2019–2025 was 100 (Moderate), in 2022.
Manchester October air quality, year by year
Manchester October air quality by year (Manchester-Nashua, NH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 31 | 0 | 39 | O3 |
| 2020 | 31 | 31 | 0 | 46 | O3 |
| 2021cleanest | 31 | 27 | 0 | 43 | O3 |
| 2022worst | 31 | 36 | 0 | 61 | O3 |
| 2023 | 31 | 31 | 0 | 90 | O3 |
| 2024 | 31 | 32 | 0 | 77 | O3 |
| 2025 | 31 | 31 | 0 | 100 | O3 |
What October air means in Manchester
A typical October day in Manchester sits in the Good range (median AQI 31), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
October's median AQI of 31 is below Manchester's whole-year median of 37, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Manchester runs below the national October norm; 0.0% of its October days topped AQI 100 versus 1.3% nationally (below average).
October is part of Manchester's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Manchester
The latest EPA AirNow observation puts Manchester's AQI at 24 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Manchester air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Manchester-Nashua, NH), 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.