Honolulu Air Quality in April
Across 2019–2025, Honolulu's April air quality had a median AQI of 32 (Good) over 210 monitored days in the Urban Honolulu, HI area. 0.0% of April days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 67.1% of days. The cleanest April on record here was 2019 (median AQI 31, 0 days above 100) and the worst was 2024 (median 34, 0 days above 100, peak AQI 47).
- Good: 97.1%
- Moderate: 2.9%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Honolulu in April?
Good on a typical day: median AQI 32 across 2019–2025, with 0.0% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓97.1% of April days were Good (AQI 0–50), 2.9% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the April peak was 59.
- ✓Best April: 2019; worst April: 2024.
Frequently asked questions
What is the air quality like in Honolulu in April?▾
Across 2019–2025, the median daily AQI in Honolulu in April was 32 (Good). 97.1% of days were Good, 2.9% Moderate, and 0.0% 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 Honolulu?▾
A typical April day in Honolulu sits in the Good range (median AQI 32), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
Which pollutant causes Honolulu's April air quality problems?▾
Ground-level ozone set the daily AQI on 67.1% of April days in Honolulu. The highest April AQI recorded in 2019–2025 was 59 (Moderate), in 2024.
Honolulu April air quality, year by year
Honolulu April air quality by year (Urban Honolulu, HI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 30 | 31 | 0 | 52 | O3 |
| 2020 | 30 | 31 | 0 | 41 | O3 |
| 2021 | 30 | 34 | 0 | 41 | O3 |
| 2022 | 30 | 33 | 0 | 53 | PM2.5 |
| 2023 | 30 | 32 | 0 | 48 | PM2.5 |
| 2024worst | 30 | 34 | 0 | 47 | O3 |
| 2025 | 30 | 31 | 0 | 59 | O3 |
What April air means in Honolulu
A typical April day in Honolulu sits in the Good range (median AQI 32), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
April's median AQI of 32 is in line with Honolulu's whole-year median of 29, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Honolulu runs below the national April norm; 0.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Honolulu's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Honolulu
The latest EPA AirNow observation puts Honolulu's AQI at 15 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Honolulu air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Urban Honolulu, HI), 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.