SmogRank / Spain / Basque Country / Donostia / San Sebastián
Donostia / San Sebastián, month by month
Donostia / San Sebastián has a measured daily mean on 985 days since 11 January 2023. Its worst month was February 2023, at 60 US AQI (13.7 µg/m³), 433rd of 1,129 cities on that month's world ranking. Its cleanest was January 2026, at 25 US AQI (4.5 µg/m³). 2025 averaged 38 US AQI (6.8 µg/m³), against 43 US AQI (7.7 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
15 months
| Month | Why |
|---|---|
| Oct 2026 | 7 of 12 days measured; a month needs 9. The others: 2 with no readings from the monitors, 3 with readings for part of the day (a day needs 18 hours). |
| Jul 2026 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | 7 of 30 days measured; a month needs 21. The others: 23 with under 18 hours of readings or readings that failed our checks. |
| May 2026 | 2 of 31 days measured; a month needs 22. The others: 29 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Feb 2026 | 8 of 28 days measured; a month needs 20. The others: 20 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | 12 of 31 days measured; a month needs 22. The others: 19 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 | 7 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| Jul 2024 | 13 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks. |
| Jun 2024 | 14 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 7 of 31 days measured; a month needs 22. The others: 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.
Donostia / San Sebastián's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2023 | 6013.7 µg/m³ | 433rdof 1,129 | Spain, France and Portugal, February 2023 |
| March 2023 | 5310.0 µg/m³ | 253rdof 911 | Europe, 4 to 7 March 2023 |
| June 2025 | 529.5 µg/m³ | 1,450thof 2,508 | – |
| June 2023 | 519.3 µg/m³ | 904thof 1,603 | – |
| August 2025 | 509.0 µg/m³ | 1,483rdof 2,901 | – |
| November 2024 | 478.4 µg/m³ | 1,230thof 2,624 | – |
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.
Donostia / San Sebastián's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 Feb 2023 | 10236.0 µg/m³ | Spain, France and Portugal, February 2023 |
| 4 Mar 2023 | 9331.4 µg/m³ | Europe, 4 to 7 March 2023 |
| 5 Mar 2023 | 9331.4 µg/m³ | Europe, 4 to 7 March 2023 |
| 5 Sept 2023 | 8527.4 µg/m³ | North-eastern Spain and France, September 2023 |
| 6 Mar 2023 | 8326.5 µg/m³ | Europe, 4 to 7 March 2023 |
| 22 Feb 2023 | 8225.7 µg/m³ | Spain, France and Portugal, February 2023 |
| 20 Feb 2023 | 8024.7 µg/m³ | Spain, France and Portugal, February 2023 |
| 19 Feb 2023 | 7823.8 µg/m³ | Spain, France and Portugal, February 2023 |
| 3 Mar 2023 | 7723.3 µg/m³ | – |
| 10 Jun 2025 | 7320.9 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, Donostia / San Sebastián, Spain, 11 Jan 2023 – 9 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/es/san-sebastian/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.
Donostia / San Sebastián now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 04:07 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).