Washington Air Quality in April
Across 2019–2025, Washington's April air quality had a median AQI of 48 (Good) over 210 monitored days in the Washington-Arlington-Alexandria, DC-VA-MD-WV area. 1.0% of April days (2 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 71.0% of days. The cleanest April on record here was 2020 (median AQI 45, 0 days above 100) and the worst was 2023 (median 53, 2 days above 100, peak AQI 115).
- Good: 56.7%
- Moderate: 42.4%
- Unhealthy for Sensitive Groups: 1.0%
- Unhealthy or worse: 0.0%
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How is the air in Washington in April?
Good on a typical day: median AQI 48 across 2019–2025, with 1.0% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓56.7% of April days were Good (AQI 0–50), 42.4% Moderate (51–100).
- ✓2 days of 210 reached AQI 101+; the April peak was 115.
- ✓Best April: 2020; worst April: 2023.
Frequently asked questions
What is the air quality like in Washington in April?▾
Across 2019–2025, the median daily AQI in Washington in April was 48 (Good). 56.7% of days were Good, 42.4% Moderate, and 1.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Washington?▾
A typical April day in Washington 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 100 of April days (1.0%) reached AQI 101+ in 2019–2025.
Which pollutant causes Washington's April air quality problems?▾
Ground-level ozone set the daily AQI on 71.0% of April days in Washington. The highest April AQI recorded in 2019–2025 was 115 (Unhealthy for Sensitive Groups), in 2023.
Washington April air quality, year by year
Washington April air quality by year (Washington-Arlington-Alexandria, DC-VA-MD-WV, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 52 | 0 | 74 | O3 |
| 2020cleanest | 30 | 45 | 0 | 62 | O3 |
| 2021 | 30 | 50 | 0 | 90 | O3 |
| 2022 | 30 | 47 | 0 | 80 | O3 |
| 2023worst | 30 | 53 | 2 | 115 | O3 |
| 2024 | 30 | 49 | 0 | 67 | O3 |
| 2025 | 30 | 47 | 0 | 90 | O3 |
What April air means in Washington
A typical April day in Washington 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 100 of April days (1.0%) reached AQI 101+ in 2019–2025.
April's median AQI of 48 is below Washington's whole-year median of 52, making it one of the area's cleaner periods. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Washington runs above the national April norm; 1.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Washington's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Washington
The latest EPA AirNow observation puts Washington's AQI at 41 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Washington air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Washington-Arlington-Alexandria, DC-VA-MD-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.