SmogRank / United States / California / Thousand Oaks
Thousand Oaks, month by month
Thousand Oaks has a measured daily mean on 1,282 days since 11 January 2023. Its worst month was September 2023, at 54 US AQI (10.5 µg/m³), 508th of 2,176 cities on that month's world ranking. Its cleanest was January 2026, at 21 US AQI (3.7 µg/m³). 2025 averaged 37 US AQI (6.7 µg/m³), against 36 US AQI (6.5 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 |
|---|---|
| Apr 2023 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 6 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 14 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.
Thousand Oaks's worst months
| Month | US AQI | World rank |
|---|---|---|
| September 2023 | 5410.5 µg/m³ | 508thof 2,176 |
| July 2023 | 5310.2 µg/m³ | 645thof 1,432 |
| August 2025 | 529.8 µg/m³ | 1,278thof 2,901 |
| June 2025 | 529.4 µg/m³ | 1,481stof 2,508 |
| May 2025 | 488.6 µg/m³ | 1,184thof 2,826 |
| June 2024 | 478.5 µg/m³ | 1,125thof 2,563 |
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.
Thousand Oaks's worst days
| Day | US AQI |
|---|---|
| 28 Jul 2026 | 14051.5 µg/m³ |
| 23 Sept 2023 | 7723.0 µg/m³ |
| 22 Sept 2023 | 7421.3 µg/m³ |
| 24 Sept 2023 | 7220.6 µg/m³ |
| 4 Dec 2024 | 7019.2 µg/m³ |
| 5 Aug 2025 | 7019.1 µg/m³ |
| 21 Sept 2023 | 6818.2 µg/m³ |
| 5 Jul 2025 | 6717.5 µg/m³ |
| 4 Aug 2025 | 6516.7 µg/m³ |
| 16 Jun 2024 | 6516.5 µg/m³ |
Daily means, the highest since 11 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, Thousand Oaks, United States, 11 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/thousand-oaks/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.
Thousand Oaks now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 00:07 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).