Charleston, WV Air Quality in May

Across 2019–2025, Charleston's May air quality had a median AQI of 42 (Good) over 217 monitored days in the Charleston, WV 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 67.3% of days. The cleanest May on record here was 2025 (median AQI 34, 0 days above 100) and the worst was 2021 (median 48, 0 days above 100, peak AQI 84).

42
Median AQI
Good
0.0%
Days above AQI 100
0 of 217 days
55
90th percentile AQI
worst 1 day in 10
84
Peak AQI
Moderate
O3
Main pollutant
67.3% of days
76.5%
Good days
166 of 217
  • Good: 76.5%
  • Moderate: 23.5%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Charleston 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.

  • 76.5% of May days were Good (AQI 0–50), 23.5% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the May peak was 84.
  • Best May: 2025; worst May: 2021.

Frequently asked questions

What is the air quality like in Charleston in May?

Across 2019–2025, the median daily AQI in Charleston in May was 42 (Good). 76.5% of days were Good, 23.5% 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 Charleston?

A typical May day in Charleston 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 Charleston's May air quality problems?

Ground-level ozone set the daily AQI on 67.3% of May days in Charleston. The highest May AQI recorded in 2019–2025 was 84 (Moderate), in 2021.

Charleston May air quality, year by year

Charleston May air quality by year (Charleston, WV, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193141080O3
20203139055O3
2021worst3148084O3
20223144074O3
20233147064PM2.5
20243140064O3
2025cleanest3134052O3

What May air means in Charleston

A typical May day in Charleston 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 in line with Charleston's whole-year median of 41, 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 Charleston 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 Charleston's spring season (March, April, May); the spring page pools all three months.

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

Right now in Charleston

The latest EPA AirNow observation puts Charleston's AQI at 55 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Charleston air quality →

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