Honolulu Air Quality in Winter
Across 2019–2025, Honolulu's winter (December–February) air quality had a median AQI of 34 (Good) over 632 monitored days in the Urban Honolulu, HI area. 0.2% of winter days (1 of 632) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 67.2% of days. The cleanest winter on record here was 2022 (median AQI 31, 0 days above 100) and the worst was 2023 (median 36, 1 day above 100, peak AQI 117).
- Good: 95.3%
- Moderate: 4.6%
- Unhealthy for Sensitive Groups: 0.2%
- Unhealthy or worse: 0.0%
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How is the air in Honolulu in winter?
Good on a typical day: median AQI 34 across 2019–2025, with 0.2% of winter days above AQI 100. Ground-level ozone is the main driver.
- ✓95.3% of winter days were Good (AQI 0–50), 4.6% Moderate (51–100).
- ✓1 day of 632 reached AQI 101+; the winter peak was 117.
- ✓Cleanest month: December; worst month: January.
Frequently asked questions
What is the air quality like in Honolulu in winter?▾
Across 2019–2025, the median daily AQI in Honolulu in winter was 34 (Good). 95.3% of days were Good, 4.6% Moderate, and 0.2% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Honolulu?▾
A typical winter day in Honolulu sits in the Good range (median AQI 34), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Which pollutant causes Honolulu's winter air quality problems?▾
Ground-level ozone set the daily AQI on 67.2% of winter days in Honolulu. The highest winter AQI recorded in 2019–2025 was 117 (Unhealthy for Sensitive Groups), in 2023.
Honolulu winter air quality, year by year
Honolulu winter air quality by year (Urban Honolulu, HI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 35 | 0 | 54 | O3 |
| 2020 | 91 | 34 | 0 | 63 | O3 |
| 2021 | 90 | 33 | 0 | 46 | O3 |
| 2022cleanest | 90 | 31 | 0 | 57 | O3 |
| 2023worst | 90 | 36 | 1 | 117 | O3 |
| 2024 | 91 | 34 | 0 | 85 | O3 |
| 2025 | 90 | 34 | 0 | 56 | O3 |
What winter air means in Honolulu
A typical winter day in Honolulu sits in the Good range (median AQI 34), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of winter days reached AQI 101+ in 2019–2025.
Winter's median AQI of 34 is above Honolulu's whole-year median of 29, making it one of the area's dirtier periods. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Honolulu runs below the national Winter norm; 0.2% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, December is the cleanest month (median AQI 31, 0.0% of days above 100) and January the worst (median 34, 0.5% above 100).
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 season 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.