Check tomorrow's forecast
AirNow posts an air quality forecast by ZIP code, usually the day before.
AirNow →Air quality in Honolulu County, HI
Includes Honolulu · EPA monitor readings, 2021 to 2025 · 1.0 million people
For today's air and tomorrow's forecast, check AirNow by ZIP code.
Bad-air days a year
<1
day with an AQI over 100
1 bad-air day in 5 years of readings, 2021 to 2025. In the early 2000s it was about 2 a year. Honolulu County has the 2nd most bad-air days of the 3 Hawaii counties with monitors.
0days unhealthy for everyoneAQI over 150, a year
30AQI on a typical dayGood: fine for everyone
1bad-air day since 2016Too few to show a season
117worst day since 2016Jan 1, 2023, fine particles
How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.
Typical day 30 (Good)Worst day 117 (Unhealthy for sensitive groups)
Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500
Bad-air days by month in Honolulu County
Bad air is rare here: 1 bad-air day in 10 years of daily readings since 2016, too few to show a season. Each tile is the average for that month.
Jan0.1
Feb0
Mar0
Apr0
May0
Jun0
Jul0
Aug0
Sep0
Oct0
Nov0
Dec0
The worst day since 2016 was January 1, 2023: AQI 117, from fine particles (New Year's fireworks are a common cause).
What causes it
The only bad-air day since 2016 was a fine-particle day, on January 1, 2023. That was New Year's Day, when fireworks smoke can push fine particles up.
What helps in Honolulu County
The air here is clean most days: 1 bad-air day in 10 years of daily readings. Wildfire smoke can still drift in from far away, so it's worth being ready.
Keep a cheap backup
A box fan with a MERV 13 filter clamped to it cleans a room in a pinch.
Build one →Keep one room clean on smoky days
Shut the windows and run an air purifier sized for the room.
Choosing a purifier →For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.
Smoky days are rare here, so a purifier is optional. If you want one for wildfire season anyway, see the 3 models we'd buy, each with a verified smoke rating.
Every year since 2000
Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. The worst recent year was 2023, with 1 bad-air day.
Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)
See the numbers by year
| Year | Bad-air days | Over 150 |
|---|---|---|
| 2000 | 2 | 2 |
| 2001 | 2 | 2 |
| 2002 | 2 | 1 |
| 2003 | 2 | 1 |
| 2004 | 2 | 2 |
| 2005 | 3 | 1 |
| 2006 | 1 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 1 | 1 |
| 2010 | 1 | 1 |
| 2011 | 1 | 0 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 1 | 1 |
| 2015 | 0 | 0 |
| 2016 | 0 | 0 |
| 2017 | 0 | 0 |
| 2018 | 0 | 0 |
| 2019 | 0 | 0 |
| 2020 | 0 | 0 |
| 2021 | 0 | 0 |
| 2022 | 0 | 0 |
| 2023 | 1 | 0 |
| 2024 | 0 | 0 |
| 2025 | 0 | 0 |
Honolulu County and its neighbors
Bad-air days a year, 2021 to 2025. Hawaii counties with monitors averaged almost no bad-air days a year, weighted by population.
Honolulu County<1
Questions people ask about air in Honolulu County
How often is the air bad in Honolulu County?
From 2021 to 2025, monitors in Honolulu County recorded almost no bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. The worst year in that stretch was 2023, with 1 bad-air day.
What causes bad air in Honolulu County?
The only bad-air day since 2016 was a fine-particle day, on January 1, 2023. That was New Year's Day, when fireworks smoke can push fine particles up.
Where can I see today's air quality in Honolulu County?
AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Honolulu County is about 30, which is good, fine for everyone. Bad days are rare here, so check it when wildfire smoke is in the news.
About these numbers
Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 365 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's modeled estimates, used on our map, don't cover Alaska or Hawaii, so the monitor numbers above are the whole picture here.
Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.