SmogRank / United States / California / Glendora
Glendora, month by month
Glendora has a measured daily mean on 1,263 days since 1 January 2023. Its worst month was July 2024, at 71 US AQI (20.1 µg/m³), 101st of 2,566 cities on that month's world ranking. Its cleanest was January 2023, at 21 US AQI (3.8 µg/m³). 2025 averaged 52 US AQI (9.9 µg/m³), against 54 US AQI (10.5 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
3 months
| Month | Why |
|---|---|
| May 2024 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| 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: 25 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Glendora's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2024 | 7120.1 µg/m³ | 101stof 2,566 | California and Nevada, United States, July 2024 |
| July 2023 | 6717.8 µg/m³ | 90thof 1,432 | California, United States, July 2023 |
| July 2026 | 6315.6 µg/m³ | 486thof 2,784 | – |
| September 2024 | 6014.0 µg/m³ | 193rdof 2,010 | – |
| June 2025 | 5913.4 µg/m³ | 612thof 2,508 | – |
| August 2025 | 5813.1 µg/m³ | 561stof 2,901 | – |
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.
Glendora's worst days
| Day | US AQI | Episode |
|---|---|---|
| 5 Jul 2024 | 237162.0 µg/m³ | California and Nevada, United States, July 2024 |
| 5 Jul 2023 | 190111.0 µg/m³ | California, United States, July 2023 |
| 5 Jul 2026 | 17386.5 µg/m³ | – |
| 5 Jul 2025 | 16270.8 µg/m³ | – |
| 9 Sept 2024 | 12846.4 µg/m³ | – |
| 10 Sept 2024 | 12143.6 µg/m³ | – |
| 4 Jul 2023 | 10838.5 µg/m³ | California, United States, July 2023 |
| 20 Jun 2026 | 10737.9 µg/m³ | – |
| 4 Jul 2026 | 10537.2 µg/m³ | – |
| 22 Dec 2024 | 9834.4 µg/m³ | California, United States, December 2024 |
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, Glendora, 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/glendora/history (accessed 12 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.
Glendora now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 19:07 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).