Manchester Air Quality in May
Across 2019–2025, Manchester's May air quality had a median AQI of 42 (Good) over 217 monitored days in the Manchester-Nashua, NH area. 0.0% of May days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 98.6% of days. The cleanest May on record here was 2025 (median AQI 37, 0 days above 100) and the worst was 2023 (median 47, 0 days above 100, peak AQI 74).
- Good: 86.6%
- Moderate: 13.4%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Manchester in May?
Good on a typical day: median AQI 42 across 2019–2025, with 0.0% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓86.6% of May days were Good (AQI 0–50), 13.4% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the May peak was 97.
- ✓Best May: 2025; worst May: 2023.
Frequently asked questions
What is the air quality like in Manchester in May?▾
Across 2019–2025, the median daily AQI in Manchester in May was 42 (Good). 86.6% of days were Good, 13.4% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is May a good time for outdoor exercise in Manchester?▾
A typical May day in Manchester sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
Which pollutant causes Manchester's May air quality problems?▾
Ground-level ozone set the daily AQI on 98.6% of May days in Manchester. The highest May AQI recorded in 2019–2025 was 97 (Moderate), in 2023.
Manchester May air quality, year by year
Manchester May 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 | 38 | 0 | 49 | O3 |
| 2020 | 31 | 43 | 0 | 51 | O3 |
| 2021 | 31 | 41 | 0 | 97 | O3 |
| 2022 | 31 | 45 | 0 | 74 | O3 |
| 2023worst | 31 | 47 | 0 | 74 | O3 |
| 2024 | 31 | 40 | 0 | 97 | O3 |
| 2025cleanest | 31 | 37 | 0 | 61 | O3 |
What May air means in Manchester
A typical May day in Manchester sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.
May's median AQI of 42 is above Manchester's whole-year median of 37, making it one of the area's dirtier periods. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Manchester runs in line with the national May norm; 0.0% of its May days topped AQI 100 versus 1.3% nationally (below average).
May is part of Manchester's spring season (March, April, May); the spring 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.