Honolulu Air Quality in December
Across 2019–2025, Honolulu's December air quality had a median AQI of 31 (Good) over 217 monitored days in the Urban Honolulu, HI area. 0.0% of December days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 67.3% of days. The cleanest December on record here was 2020 (median AQI 28, 0 days above 100) and the worst was 2021 (median 38, 0 days above 100, peak AQI 46).
- Good: 95.4%
- Moderate: 4.6%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Honolulu in December?
Good on a typical day: median AQI 31 across 2019–2025, with 0.0% of December days above AQI 100. Ground-level ozone is the main driver.
- ✓95.4% of December days were Good (AQI 0–50), 4.6% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the December peak was 64.
- ✓Best December: 2020; worst December: 2021.
Frequently asked questions
What is the air quality like in Honolulu in December?▾
Across 2019–2025, the median daily AQI in Honolulu in December was 31 (Good). 95.4% of days were Good, 4.6% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is December a good time for outdoor exercise in Honolulu?▾
A typical December day in Honolulu sits in the Good range (median AQI 31), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
Which pollutant causes Honolulu's December air quality problems?▾
Ground-level ozone set the daily AQI on 67.3% of December days in Honolulu. The highest December AQI recorded in 2019–2025 was 64 (Moderate), in 2021.
Honolulu December air quality, year by year
Honolulu December 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 | 32 | 0 | 54 | O3 |
| 2020cleanest | 31 | 28 | 0 | 52 | O3 |
| 2021worst | 31 | 38 | 0 | 46 | O3 |
| 2022 | 31 | 32 | 0 | 57 | PM2.5 |
| 2023 | 31 | 32 | 0 | 64 | O3 |
| 2024 | 31 | 28 | 0 | 51 | O3 |
| 2025 | 31 | 31 | 0 | 46 | O3 |
What December air means in Honolulu
A typical December day in Honolulu sits in the Good range (median AQI 31), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
December's median AQI of 31 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 December AQI across every EPA metro area (95,590 metro-days, 2019–2025) is 39, so Honolulu runs below the national December norm; 0.0% of its December days topped AQI 100 versus 0.7% nationally (about the same).
December is part of Honolulu's winter season (December, January, February); the winter 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.