SmogRank / Brazil / São Paulo / Rio Claro
Rio Claro, month by month
Rio Claro has a measured daily mean on 1,269 days since 1 January 2023. Its worst month was September 2024, at 124 US AQI (44.7 µg/m³), 11th of 2,010 cities on that month's world ranking. Its cleanest was January 2023, at 46 US AQI (8.3 µg/m³). 2025 averaged 64 US AQI (16.1 µg/m³), against 72 US AQI (20.4 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
5 months
| Month | Why |
|---|---|
| May 2026 | 10 of 31 days measured; a month needs 22. The others: 21 with no readings from the monitors. |
| Jun 2024 | 19 of 30 days measured; a month needs 21. The others: 10 with no readings from the monitors, 1 with readings for part of the day (a day needs 18 hours). |
| May 2024 | 16 of 31 days measured; a month needs 22. The others: 14 with no readings from the monitors, 1 with readings for part of the day (a day needs 18 hours). |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Rio Claro's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| September 2024 | 12444.7 µg/m³ | 11thof 2,010 | Southern Brazil, 30 September to 4 October 2024 Southern Brazil, 22 to 28 September 2024and 2 more |
| August 2024 | 9331.8 µg/m³ | 45thof 2,010 | Southern Brazil, 30 August to 5 September 2024 Southern Brazil, 22 to 25 August 2024and 1 more |
| July 2024 | 8326.3 µg/m³ | 69thof 2,566 | Southern Brazil, 25 to 28 July 2024 |
| July 2025 | 7722.9 µg/m³ | 156thof 2,889 | Southern Brazil, July 2025 |
| August 2023 | 7622.7 µg/m³ | 98thof 1,980 | – |
| August 2025 | 7522.1 µg/m³ | 171stof 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.
Rio Claro's worst days
| Day | US AQI | Episode |
|---|---|---|
| 9 Sept 2024 | 17589.2 µg/m³ | Southern Brazil, 7 to 17 September 2024 |
| 3 Sept 2024 | 17285.7 µg/m³ | Southern Brazil, 30 August to 5 September 2024 |
| 10 Sept 2024 | 16981.0 µg/m³ | Southern Brazil, 7 to 17 September 2024 |
| 8 Sept 2024 | 16270.5 µg/m³ | Southern Brazil, 7 to 17 September 2024 |
| 17 Aug 2024 | 16170.2 µg/m³ | Southern Brazil, 15 to 22 August 2024 |
| 2 Sept 2024 | 16169.8 µg/m³ | Southern Brazil, 30 August to 5 September 2024 |
| 5 Sept 2024 | 16068.7 µg/m³ | Southern Brazil, 30 August to 5 September 2024 |
| 4 Sept 2024 | 15764.5 µg/m³ | Southern Brazil, 30 August to 5 September 2024 |
| 23 Aug 2024 | 15459.2 µg/m³ | Southern Brazil, 22 to 25 August 2024 |
| 22 Aug 2024 | 15257.0 µg/m³ | Southern Brazil, 22 to 25 August 2024 Southern Brazil, 15 to 22 August 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, Rio Claro, Brazil, 1 Jan 2023 – 11 Oct 2026. Monitor data from CETESB, read from the publisher; sources listed at smogrank.com/sources. smogrank.com/br/rio-claro/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.
Rio Claro 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).