SmogRank / Chile / Ñuble / San Carlos
San Carlos, month by month
San Carlos, Ñuble has a measured daily mean on 1,111 days since 1 January 2023. Its worst month was May 2024, at 167 US AQI (77.8 µg/m³), 10th of 2,684 cities on that month's world ranking. Its cleanest was December 2025, at 62 US AQI (14.8 µg/m³). 2025 averaged 97 US AQI (33.8 µg/m³), against 101 US AQI (35.5 µg/m³) in 2023.
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
9 months
| Month | Why |
|---|---|
| Feb 2026 | 14 of 28 days measured; a month needs 20. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2024 | 10 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 9 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
| Jan 2023 | 21 of 31 days measured; a month needs 22. The others: 6 missing from OpenAQ's archive, 4 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.
San Carlos's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| May 2024 | 16777.8 µg/m³ | 10thof 2,684 | South-western Chile, 24 to 28 May 2024 South-western Chile, 14 to 19 May 2024and 1 more |
| June 2025 | 16067.7 µg/m³ | 12thof 2,508 | Southern Chile, 29 June to 4 July 2025 South-western Chile, June 2025and 1 more |
| June 2023 | 15459.7 µg/m³ | 10thof 1,603 | South-western Chile, June 2023 Southern Chile, June 2023 |
| May 2026 | 15358.0 µg/m³ | 36thof 2,874 | Chile, May 2026 South-western Chile, May 2026 |
| July 2025 | 15357.7 µg/m³ | 22ndof 2,889 | Southern Chile, 29 June to 4 July 2025 |
| July 2023 | 15055.4 µg/m³ | 9thof 1,432 | Southern Chile, July 2023 |
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.
San Carlos's worst days
| Day | US AQI | Episode |
|---|---|---|
| 3 Jul 2025 | 288213.0 µg/m³ | Southern Chile, 29 June to 4 July 2025 |
| 30 Jun 2024 | 270195.0 µg/m³ | Southern Chile, 30 June to 1 July 2024 |
| 2 Jul 2025 | 259184.0 µg/m³ | Southern Chile, 29 June to 4 July 2025 |
| 25 May 2024 | 255180.0 µg/m³ | South-western Chile, 24 to 28 May 2024 |
| 18 May 2024 | 254179.0 µg/m³ | South-western Chile, 14 to 19 May 2024 |
| 18 Jul 2023 | 245170.0 µg/m³ | Southern Chile, July 2023 |
| 14 Jun 2023 | 240165.0 µg/m³ | Southern Chile, June 2023 |
| 24 May 2024 | 238163.0 µg/m³ | South-western Chile, 24 to 28 May 2024 |
| 25 May 2026 | 229154.0 µg/m³ | Chile, May 2026 |
| 26 May 2026 | 229154.0 µg/m³ | Chile, May 2026 |
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, San Carlos, Ñuble, Chile, 1 Jan 2023 – 11 Oct 2026. Monitor data from Chile - SINCA via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/cl/san-carlos/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.
San Carlos now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 01:07 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).