Honolulu Air Quality in October
Across 2019–2025, Honolulu's October air quality had a median AQI of 25 (Good) over 217 monitored days in the Urban Honolulu, HI area. 0.0% of October days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 59.4% of days. The cleanest October on record here was 2021 (median AQI 21, 0 days above 100) and the worst was 2022 (median 30, 0 days above 100, peak AQI 39).
- Good: 99.5%
- Moderate: 0.5%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Honolulu
Today's main pollutant in Honolulu is ground-level ozone (AQI 28). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Honolulu in October?
Good on a typical day: median AQI 25 across 2019–2025, with 0.0% of October days above AQI 100. Ground-level ozone is the main driver.
- ✓99.5% of October days were Good (AQI 0–50), 0.5% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the October peak was 55.
- ✓Best October: 2021; worst October: 2022.
Frequently asked questions
What is the air quality like in Honolulu in October?▾
Across 2019–2025, the median daily AQI in Honolulu in October was 25 (Good). 99.5% of days were Good, 0.5% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Honolulu?▾
A typical October day in Honolulu sits in the Good range (median AQI 25), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
Which pollutant causes Honolulu's October air quality problems?▾
Ground-level ozone set the daily AQI on 59.4% of October days in Honolulu. The highest October AQI recorded in 2019–2025 was 55 (Moderate), in 2022.
Honolulu October air quality, year by year
Honolulu October 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 | 25 | 0 | 30 | O3 |
| 2020 | 31 | 27 | 0 | 44 | PM2.5 |
| 2021cleanest | 31 | 21 | 0 | 37 | O3 |
| 2022worst | 31 | 30 | 0 | 39 | O3 |
| 2023 | 31 | 24 | 0 | 55 | O3 |
| 2024 | 31 | 25 | 0 | 49 | O3 |
| 2025 | 31 | 25 | 0 | 35 | O3 |
What October air means in Honolulu
A typical October day in Honolulu sits in the Good range (median AQI 25), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of October days reached AQI 101+ in 2019–2025.
October's median AQI of 25 is below Honolulu's whole-year median of 29, making it one of the area's cleaner periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Honolulu runs below the national October norm; 0.0% of its October days topped AQI 100 versus 1.3% nationally (below average).
October is part of Honolulu's fall season (September, October, November); the fall 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 28 (O3). 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.