SmogRank / United States / California / Santa Monica
Santa Monica, month by month
Santa Monica has a measured daily mean on 1,279 days since 1 January 2023. Its worst month was May 2025, at 65 US AQI (16.4 µg/m³), 357th of 2,826 cities on that month's world ranking. Its cleanest was January 2023, at 28 US AQI (5.1 µg/m³). 2025 averaged 58 US AQI (12.8 µg/m³), against 52 US AQI (9.6 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 |
|---|---|
| Jun 2023 | 17 of 30 days measured; a month needs 21. The others: 13 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: 19 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks. |
| 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.
Santa Monica's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| May 2025 | 6516.4 µg/m³ | 357thof 2,826 | – |
| December 2024 | 6315.4 µg/m³ | 442ndof 2,616 | California, United States, December 2024 California and Oregon, United States, December 2024 |
| June 2025 | 6215.2 µg/m³ | 426thof 2,508 | – |
| December 2025 | 6114.3 µg/m³ | 774thof 3,006 | Western United States and Mexico, December 2025 |
| November 2025 | 6114.2 µg/m³ | 616thof 2,715 | California, United States, November 2025 |
| April 2025 | 6013.8 µg/m³ | 599thof 2,951 | – |
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.
Santa Monica's worst days
| Day | US AQI | Episode |
|---|---|---|
| 5 Jul 2025 | 11641.4 µg/m³ | – |
| 2 Nov 2025 | 10738.1 µg/m³ | California, United States, November 2025 |
| 9 Jan 2025 | 10537.3 µg/m³ | – |
| 25 Oct 2025 | 9934.9 µg/m³ | – |
| 27 Oct 2025 | 9633.2 µg/m³ | – |
| 15 Dec 2025 | 9532.9 µg/m³ | Western United States and Mexico, December 2025 |
| 19 May 2026 | 9331.5 µg/m³ | – |
| 5 Dec 2024 | 9331.4 µg/m³ | California and Oregon, United States, December 2024 |
| 10 Jan 2025 | 8929.6 µg/m³ | – |
| 29 Nov 2025 | 8929.5 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, Santa Monica, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from Clarity and AirGradient via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/us/santa-monica/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.
Santa Monica now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 02:07 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).