SmogRank / Ireland / Connacht / Sligo

Sligo, month by month

Sligo has a measured daily mean on 253 days since 24 June 2025. Its worst month was August 2025, at 44 US AQI (8.0 µg/m³), 1,820th of 2,901 cities on that month's world ranking. Its cleanest was July 2026, at 27 US AQI (4.9 µg/m³).

Every month since 2025

2026too few days for a mean (a year needs 199)181 days measured
Jan5 daysFeb2 daysMar4 daysApr31#2,337May28#2,348Jun20 daysJul27#2,607Aug31#2,642Sep32#1,947Oct31#1,987
2025too few days for a mean (a year needs 256)72 days measured
JanFebMarAprMayJun4 daysJul18 daysAug44#1,820Sep15 daysOct8 daysNovnoneDecnone
Each square is a month's mean PM2.5 in US AQI from Sligo'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 Sligo marked; each year, the year's. A dashed square is the running month, so far.
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

10 months
MonthWhy
Jun 202620 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Mar 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Feb 20262 of 28 days measured; a month needs 20. The others: 26 with under 18 hours of readings or readings that failed our checks.
Jan 20265 of 31 days measured; a month needs 22. The others: 26 with under 18 hours of readings or readings that failed our checks.
Dec 2025No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Nov 2025No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks.
Oct 20258 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Sep 202515 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks.
Jul 202518 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jun 20254 of 30 days measured; a month needs 21. The others: 3 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.

Sligo's worst months

MonthUS AQIDays measuredWorld rank
August 2025 448.0 µg/m³27 of 311,820thof 2,901
September 2026 325.7 µg/m³26 of 301,947thof 2,981
April 2026 315.6 µg/m³29 of 302,337thof 2,941
August 2026 315.5 µg/m³27 of 312,642ndof 2,896
May 2026 285.0 µg/m³29 of 312,348thof 2,874
July 2026 274.9 µg/m³30 of 312,607thof 2,784

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.

Sligo's worst days

DayUS AQI
12 Aug 2025 8225.7 µg/m³
24 Jul 2025 7119.8 µg/m³
11 Sept 2026 6818.4 µg/m³
30 Mar 2026 6617.4 µg/m³
27 Aug 2026 6617.1 µg/m³
13 Aug 2025 6315.7 µg/m³
15 Jul 2026 5913.6 µg/m³
29 Mar 2026 5913.3 µg/m³
17 Sept 2026 5812.7 µg/m³
17 Jul 2026 5612.0 µg/m³

Daily means, the highest since 24 Jun 2025; 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, Sligo, Ireland, 24 Jun 2025 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/ie/sligo/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.

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

Updated 2026-10-12 20:07 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).