SmogRank / United States / California / Crestline
Crestline, month by month
Crestline has a measured daily mean on 1,256 days since 1 January 2023. Its worst month was September 2024, at 58 US AQI (12.8 µg/m³), 241st of 2,010 cities on that month's world ranking. Its cleanest was December 2025, at 22 US AQI (4.0 µg/m³). 2025 averaged 35 US AQI (6.3 µg/m³), against 39 US AQI (7.1 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.
Crestline's worst months
| Month | US AQI | World rank |
|---|---|---|
| September 2024 | 5812.8 µg/m³ | 241stof 2,010 |
| July 2023 | 519.2 µg/m³ | 736thof 1,432 |
| August 2025 | 498.8 µg/m³ | 1,551stof 2,901 |
| June 2024 | 488.7 µg/m³ | 1,036thof 2,563 |
| June 2023 | 488.6 µg/m³ | 1,008thof 1,603 |
| December 2023 | 468.3 µg/m³ | 1,178thof 2,247 |
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.
Crestline's worst days
| Day | US AQI |
|---|---|
| 8 Sept 2024 | 14051.4 µg/m³ |
| 14 Sept 2024 | 9633.2 µg/m³ |
| 7 Sept 2024 | 8628.1 µg/m³ |
| 13 Sept 2024 | 7924.2 µg/m³ |
| 4 Aug 2025 | 7723.2 µg/m³ |
| 31 Jul 2023 | 7622.6 µg/m³ |
| 12 Sept 2024 | 7421.4 µg/m³ |
| 15 Sept 2024 | 7321.1 µg/m³ |
| 3 Aug 2025 | 7119.6 µg/m³ |
| 9 Sept 2024 | 7019.3 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, Crestline, United States, 1 Jan 2023 – 10 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/crestline/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.
Crestline 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).