SmogRank / United States / Hawaii / Honolulu

Honolulu, month by month

Honolulu has a measured daily mean on 1,353 days since 1 January 2023. Its worst month was January 2024, at 35 US AQI (6.3 µg/m³), 1,737th of 2,385 cities on that month's world ranking. Its cleanest was August 2026, at 17 US AQI (3.0 µg/m³). 2025 averaged 23 US AQI (4.2 µg/m³), against 23 US AQI (4.1 µg/m³) in 2024.

Every month since 2023

202623 so far280 days measured2,727th of 2,791 in the world

Jan31#2,250 Feb31#2,522 Mar29#2,638 Apr22#2,713 May25#2,508 Jun19#2,374 Jul18#2,743 Aug17#2,881 Sep22#2,768 Oct14#2,704

202523 for the year358 days measured2,621st of 2,681 in the world

Jan26#2,280 Feb27#2,394 Mar29#2,447 Apr29#2,506 May22#2,600 Jun21#2,423 Jul19#2,820 Aug20#2,842 Sep19#3,013 Oct21#2,475 Nov25#2,502 Dec24#2,821

202423 for the year358 days measured2,041st of 2,097 in the world

Jan35#1,737 Feb26#2,218 Mar26#1,396 Apr28#1,973 May23#2,411 Jun22#2,398 Jul19#2,501 Aug19#1,982 Sep17#1,984 Oct19#1,975 Nov21#2,491 Dec23#2,441

202323 for the year357 days measured1,324th of 1,355 in the world

Jan31#1,037 Feb28#1,061 Mar26#823 Apr20#1,514 May20#1,551 Jun17#1,565 Jul24#1,304 Aug29#1,792 Sep21#2,121 Oct17#1,975 Nov22#2,134 Dec24#2,095

Each square is a month's mean PM2.5 in US AQI from Honolulu's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Honolulu marked; each year, the year's. A dashed square is the running month, so far.

Good0–50

Moderate51–100

Sensitive groups101–150

Unhealthy151–200

Very unhealthy201–300

Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Honolulu's worst months

Month	US AQI	Days measured	World rank
January 2024	356.3 µg/m³	30 of 31	1,737thof 2,385
January 2023	315.5 µg/m³	30 of 31	1,037thof 1,261
January 2026	315.5 µg/m³	29 of 31	2,250thof 2,617
February 2026	315.5 µg/m³	28 of 28	2,522ndof 2,866
March 2026	295.3 µg/m³	31 of 31	2,638thof 2,971
August 2023	295.2 µg/m³	31 of 31	1,792ndof 1,980

Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.

Honolulu's worst days

Day	US AQI
1 Jan 2024	7321.0 µg/m³
1 Jan 2023	6818.1 µg/m³
8 Aug 2023	6516.8 µg/m³
31 Dec 2023	6416.3 µg/m³
4 Apr 2025	5812.6 µg/m³
10 Jan 2023	5712.5 µg/m³
15 Mar 2026	5712.3 µg/m³
9 Aug 2023	5712.2 µg/m³
7 Aug 2023	5611.6 µg/m³
28 Mar 2025	5511.3 µg/m³

Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.

Use this history

SmogRank, PM2.5 monthly and daily means, Honolulu, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/honolulu/history (accessed 12 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

Honolulu now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 18:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).