Honolulu Air Quality in May
Across 2019–2025, Honolulu's May air quality had a median AQI of 30 (Good) over 217 monitored days in the Urban Honolulu, HI 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 65.9% of days. The cleanest May on record here was 2020 (median AQI 24, 0 days above 100) and the worst was 2023 (median 36, 0 days above 100, peak AQI 53).
- Good: 98.6%
- Moderate: 1.4%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Honolulu in May?
Good on a typical day: median AQI 30 across 2019–2025, with 0.0% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓98.6% of May days were Good (AQI 0–50), 1.4% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the May peak was 54.
- ✓Best May: 2020; worst May: 2023.
Frequently asked questions
What is the air quality like in Honolulu in May?▾
Across 2019–2025, the median daily AQI in Honolulu in May was 30 (Good). 98.6% of days were Good, 1.4% 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 Honolulu?▾
A typical May day in Honolulu sits in the Good range (median AQI 30), 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 Honolulu's May air quality problems?▾
Ground-level ozone set the daily AQI on 65.9% of May days in Honolulu. The highest May AQI recorded in 2019–2025 was 54 (Moderate), in 2023.
Honolulu May air quality, year by year
Honolulu May air quality by year (Urban Honolulu, HI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 29 | 0 | 54 | O3 |
| 2020cleanest | 31 | 24 | 0 | 36 | O3 |
| 2021 | 31 | 28 | 0 | 33 | O3 |
| 2022 | 31 | 32 | 0 | 49 | PM2.5 |
| 2023worst | 31 | 36 | 0 | 53 | PM2.5 |
| 2024 | 31 | 32 | 0 | 44 | O3 |
| 2025 | 31 | 29 | 0 | 36 | O3 |
What May air means in Honolulu
A typical May day in Honolulu sits in the Good range (median AQI 30), 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 30 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 May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Honolulu 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 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.