SmogRank / Spain / Galicia / Santiago de Compostela

Santiago de Compostela, month by month

Santiago de Compostela has a measured daily mean on 1,004 days since 1 January 2023. Its worst month was February 2023, at 58 US AQI (12.7 µg/m³), 498th of 1,129 cities on that month's world ranking. Its cleanest was September 2023, at 17 US AQI (3.0 µg/m³). 2025 averaged 35 US AQI (6.3 µg/m³), against 36 US AQI (6.5 µg/m³) in 2023.

Every month since 2023

2026too few days for a mean (a year needs 200)105 days measured
Jan47#1,358Feb8 daysMarnoneAprnoneMaynoneJun6 daysJul18 daysAug20 daysSep51#744Oct5 days
202535 for the year313 days measured2,291st of 2,681 in the world
Jan38#1,766Feb40#1,779Mar33#2,302Apr32#2,364May33#1,943Jun20 daysJul25#2,705Aug37#2,290Sep28#2,600Oct34#1,506Nov35#2,100Dec52#1,404
2024too few days for a mean (a year needs 257)248 days measured
Jan51#1,007Feb52#688Mar14 daysApr36#1,556May27#2,289Jun31#2,133Jul14 daysAug7 daysSepnoneOct13 daysNov44#1,384Dec53#888
202336 for the year338 days measured1,118th of 1,355 in the world
Jan32#1,022Feb58#498Mar39#624Apr31#1,272May38#1,173Jun32#1,339Jul18#1,382Aug21#1,942Sep17#2,153Oct33#1,526Nov41#1,320Dec53#658
Each square is a month's mean PM2.5 in US AQI from Santiago de Compostela's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Santiago de Compostela marked; each year, the year's.
Good0–50
Moderate51–100
Unhealthy for sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

14 months
MonthWhy
Oct 20265 of 12 days measured; a month needs 9. The others: 2 with no readings from the monitors, 5 with readings for part of the day (a day needs 18 hours).
Aug 202620 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jul 202618 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jun 20266 of 30 days measured; a month needs 21. The others: 24 with under 18 hours of readings or readings that failed our checks.
May 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Apr 2026No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Mar 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Feb 20268 of 28 days measured; a month needs 20. The others: 20 with under 18 hours of readings or readings that failed our checks.
Jun 202520 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Oct 202413 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Sep 2024No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Aug 20247 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Jul 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Mar 202414 of 31 days measured; a month needs 22. The others: 17 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.

Santiago de Compostela's worst months

MonthUS AQIDays measuredWorld rankEpisode
February 2023 5812.7 µg/m³28 of 28498thof 1,129Spain, France and Portugal, February 2023
December 2023 5310.2 µg/m³31 of 31658thof 2,247–
December 2024 5310.0 µg/m³26 of 31888thof 2,616–
February 2024 529.8 µg/m³29 of 29688thof 2,486–
December 2025 529.7 µg/m³28 of 311,404thof 3,006–
September 2026 519.3 µg/m³26 of 30744thof 2,997–

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.

Santiago de Compostela's worst days

DayUS AQIEpisode
10 Dec 2023 10537.0 µg/m³–
26 Nov 2023 8628.0 µg/m³–
21 Feb 2023 8527.3 µg/m³Spain, France and Portugal, February 2023
24 Jun 2023 8024.7 µg/m³–
24 Jun 2026 8024.5 µg/m³–
6 Feb 2024 7723.1 µg/m³–
1 Feb 2024 7622.5 µg/m³–
19 Feb 2023 7622.3 µg/m³Spain, France and Portugal, February 2023
20 Feb 2023 7421.4 µg/m³Spain, France and Portugal, February 2023
4 Feb 2024 7421.3 µg/m³–

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, Santiago de Compostela, Spain, 1 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/santiago-de-compostela/history (accessed 13 Oct 2026).

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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.

Santiago de Compostela now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-13 03:07 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).