SmogRank / United States / California / Riverside
Riverside, month by month
Riverside has a measured daily mean on 1,294 days since 1 January 2023. Its worst month was December 2024, at 74 US AQI (21.4 µg/m³), 211th of 2,616 cities on that month's world ranking. Its cleanest was March 2024, at 36 US AQI (6.5 µg/m³). 2025 averaged 57 US AQI (12.5 µg/m³), against 58 US AQI (12.7 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 | 4 of 30 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 25 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 | 16 of 31 days measured; a month needs 22. The others: 15 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.
Riverside's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2024 | 7421.4 µg/m³ | 211thof 2,616 | South-western United States and Mexico, December 2024 to January 2025 California, United States, December 2024and 1 more |
| November 2025 | 6818.0 µg/m³ | 464thof 2,715 | California, United States, November 2025 |
| July 2023 | 6717.5 µg/m³ | 96thof 1,432 | California, United States, July 2023 |
| December 2025 | 6717.5 µg/m³ | 619thof 3,006 | Western United States and Mexico, December 2025 |
| September 2024 | 6617.1 µg/m³ | 127thof 2,010 | – |
| July 2026 | 6315.6 µg/m³ | 486thof 2,784 | – |
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.
Riverside's worst days
| Day | US AQI | Episode |
|---|---|---|
| 5 Jul 2023 | 16474.1 µg/m³ | California, United States, July 2023 |
| 5 Jul 2026 | 15967.2 µg/m³ | – |
| 9 Sept 2024 | 15257.3 µg/m³ | – |
| 5 Jul 2024 | 15256.8 µg/m³ | California and Nevada, United States, July 2024 |
| 22 Jan 2026 | 14754.2 µg/m³ | California, United States, 21 to 22 January 2026 |
| 5 Dec 2024 | 14553.5 µg/m³ | California and Oregon, United States, December 2024 |
| 14 Dec 2025 | 14453.1 µg/m³ | Western United States and Mexico, December 2025 |
| 1 Jan 2025 | 13348.5 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
| 8 Sept 2024 | 12143.6 µg/m³ | – |
| 22 Dec 2024 | 11641.6 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, Riverside, 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/riverside/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.
Riverside 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).