Burlington Air Quality in May

Across 2019–2025, Burlington's May air quality had a median AQI of 40 (Good) over 217 monitored days in the Burlington-South Burlington, VT 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 83.9% of days. The cleanest May on record here was 2025 (median AQI 35, 0 days above 100) and the worst was 2023 (median 43, 0 days above 100, peak AQI 80).

40
Median AQI
Good
0.0%
Days above AQI 100
0 of 217 days
53
90th percentile AQI
worst 1 day in 10
84
Peak AQI
Moderate
O3
Main pollutant
83.9% of days
87.6%
Good days
190 of 217
  • Good: 87.6%
  • Moderate: 12.4%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Burlington in May?

Good on a typical day: median AQI 40 across 2019–2025, with 0.0% of May days above AQI 100. Ground-level ozone is the main driver.

  • 87.6% of May days were Good (AQI 0–50), 12.4% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the May peak was 84.
  • Best May: 2025; worst May: 2023.

Frequently asked questions

What is the air quality like in Burlington in May?

Across 2019–2025, the median daily AQI in Burlington in May was 40 (Good). 87.6% of days were Good, 12.4% 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 Burlington?

A typical May day in Burlington sits in the Good range (median AQI 40), 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 Burlington's May air quality problems?

Ground-level ozone set the daily AQI on 83.9% of May days in Burlington. The highest May AQI recorded in 2019–2025 was 84 (Moderate), in 2023.

Burlington May air quality, year by year

Burlington May air quality by year (Burlington-South Burlington, VT, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193138046O3
20203143061O3
20213141084O3
20223142058O3
2023worst3143080O3
20243139064O3
2025cleanest3135051O3

What May air means in Burlington

A typical May day in Burlington sits in the Good range (median AQI 40), 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 40 is in line with Burlington's whole-year median of 39, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Burlington runs below the national May norm; 0.0% of its May days topped AQI 100 versus 1.3% nationally (below average).

May is part of Burlington's spring season (March, April, May); the spring page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Burlington

The latest EPA AirNow observation puts Burlington's AQI at 27 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Burlington air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Burlington-South Burlington, VT), 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.