SmogRank / Spain / Basque Country / Zarautz

Zarautz, month by month

Zarautz has a measured daily mean on 890 days since 11 January 2023. Its worst month was August 2025, at 55 US AQI (11.3 µg/m³), 936th of 2,901 cities on that month's world ranking. Its cleanest was December 2023, at 17 US AQI (3.0 µg/m³). 2025 averaged 32 US AQI (5.8 µg/m³), against 27 US AQI (4.8 µg/m³) in 2023.

Every month since 2023

2026too few days for a mean (a year needs 200)102 days measured
Jan18#2,560Feb8 daysMarnoneAprnoneMay2 daysJun4 daysJul8 daysAug48#1,296Sep51#744Oct7 days
202532 for the year286 days measured2,403rd of 2,681 in the world
Jan19#2,416Feb19 daysMar20 daysApr30#2,443May34#1,862Jun19 daysJul39#2,005Aug55#936Sep32#2,242Oct20 daysNov18#2,638Dec23#2,831
2024too few days for a mean (a year needs 257)203 days measured
Jan27#2,113Feb24#2,258Mar15 daysApr27#2,029May23#2,411Jun13 daysJul9 daysAug4 daysSepnoneOct5 daysNov28#2,271Dec22#2,454
202327 for the year299 days measured1,279th of 1,355 in the world
Jan7 daysFeb41#881Mar31#761Apr24#1,430May32#1,323Jun35#1,291Jul26#1,280Aug21 daysSep19 daysOct27#1,785Nov17#2,194Dec17#2,204
Each square is a month's mean PM2.5 in US AQI from Zarautz'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 Zarautz marked; each year, the year's.
Good0–50
Moderate51–100
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

20 months
MonthWhy
Oct 20267 of 12 days measured; a month needs 9. The others: 2 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours).
Jul 20268 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Jun 20264 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks.
May 20262 of 31 days measured; a month needs 22. The others: 29 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.
Oct 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jun 202519 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Mar 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Feb 202519 of 28 days measured; a month needs 20. The others: 9 with under 18 hours of readings or readings that failed our checks.
Oct 20245 of 31 days measured; a month needs 22. The others: 26 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 20244 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Jul 20249 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Jun 202413 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks.
Mar 202415 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Sep 202319 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Aug 202321 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Jan 20237 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.

Zarautz's worst months

MonthUS AQIDays measuredWorld rank
August 2025 5511.3 µg/m³26 of 31936thof 2,901
September 2026 519.3 µg/m³28 of 30744thof 2,981
August 2026 488.7 µg/m³22 of 311,296thof 2,896
February 2023 417.4 µg/m³26 of 28881stof 1,129
July 2025 397.0 µg/m³27 of 312,005thof 2,889
June 2023 356.3 µg/m³22 of 301,291stof 1,603

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.

Zarautz's worst days

DayUS AQI
12 Aug 2025 7622.5 µg/m³
25 Jun 2026 7421.4 µg/m³
10 Jun 2025 7220.5 µg/m³
4 Aug 2025 7119.9 µg/m³
11 Aug 2025 7019.4 µg/m³
9 Apr 2025 6818.2 µg/m³
18 Feb 2023 6717.8 µg/m³
20 Feb 2023 6617.2 µg/m³
22 Feb 2023 6516.4 µg/m³
5 Mar 2023 6315.8 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, Zarautz, 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/zarautz/history (accessed 12 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.

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

Updated 2026-10-12 23:07 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).