SmogRank / United States / California / Huron
Huron, month by month
Huron has a measured daily mean on 1,280 days since 1 January 2023. Its worst month was December 2024, at 62 US AQI (14.9 µg/m³), 482nd of 2,616 cities on that month's world ranking. Its cleanest was March 2025, at 16 US AQI (2.9 µg/m³). 2025 averaged 34 US AQI (6.2 µg/m³), against 43 US AQI (7.8 µg/m³) in 2024.
Every month since 2023
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
Months without a mean, and why
2 months
| Month | Why |
|---|---|
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 2 with readings for part of the day (a day needs 18 hours), 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Huron's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2024 | 6214.9 µg/m³ | 482ndof 2,616 | California and Oregon, United States, December 2024 |
| December 2023 | 5511.1 µg/m³ | 521stof 2,247 | – |
| July 2024 | 5410.7 µg/m³ | 597thof 2,566 | – |
| August 2026 | 509.0 µg/m³ | 1,181stof 2,896 | – |
| September 2023 | 498.9 µg/m³ | 807thof 2,176 | – |
| August 2024 | 498.8 µg/m³ | 929thof 2,010 | – |
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.
Huron's worst days
| Day | US AQI | Episode |
|---|---|---|
| 4 Sept 2024 | 10236.1 µg/m³ | – |
| 8 Dec 2024 | 10235.8 µg/m³ | California and Oregon, United States, December 2024 |
| 6 Dec 2024 | 9633.3 µg/m³ | California and Oregon, United States, December 2024 |
| 7 Dec 2024 | 9633.0 µg/m³ | California and Oregon, United States, December 2024 |
| 4 Dec 2024 | 9030.3 µg/m³ | California and Oregon, United States, December 2024 |
| 5 Dec 2024 | 9029.9 µg/m³ | California and Oregon, United States, December 2024 |
| 3 Dec 2024 | 8929.6 µg/m³ | California and Oregon, United States, December 2024 |
| 1 Dec 2024 | 8929.5 µg/m³ | California and Oregon, United States, December 2024 |
| 2 Dec 2024 | 8929.3 µg/m³ | California and Oregon, United States, December 2024 |
| 30 Aug 2023 | 8326.5 µg/m³ | North-western United States and Canada, August 2023 |
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, Huron, 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/huron-california/history (accessed 13 Oct 2026).
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.
Huron now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 03:07 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).