SmogRank / Norway / Oslo / Oslo
Oslo, month by month
Oslo has a measured daily mean on 985 days since 1 January 2023. Its worst month was January 2024, at 68 US AQI (18.2 µg/m³), 325th of 2,385 cities on that month's world ranking. Its cleanest was May 2025, at 24 US AQI (4.4 µg/m³). 2025 averaged 38 US AQI (6.9 µg/m³), against 43 US AQI (7.8 µg/m³) in 2024.
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 | 5 of 11 days measured; a month needs 8. The others: 6 with readings for part of the day (a day needs 18 hours). |
| Sep 2026 | 1 of 30 days measured; a month needs 21. The others: 29 with readings for part of the day (a day needs 18 hours). |
| Aug 2026 | 1 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 3 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Dec 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. |
| Nov 2025 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Dec 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Nov 2023 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | 4 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 4 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 11 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks. |
| May 2023 | 17 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.
Oslo's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2024 | 6818.2 µg/m³ | 325thof 2,385 | Southern Norway, 18 to 20 January 2024 Southern Norway, 12 to 13 January 2024and 1 more |
| February 2025 | 5410.5 µg/m³ | 1,132ndof 2,633 | – |
| January 2023 | 5310.3 µg/m³ | 447thof 1,261 | – |
| February 2023 | 5310.2 µg/m³ | 658thof 1,129 | – |
| November 2024 | 529.5 µg/m³ | 946thof 2,624 | – |
| January 2025 | 529.4 µg/m³ | 1,099thof 2,474 | Southern Norway, 4 January 2025 |
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.
Oslo's worst days
| Day | US AQI | Episode |
|---|---|---|
| 9 Jan 2024 | 14754.0 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 10 Jan 2024 | 11039.3 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 8 Jan 2024 | 10436.7 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 1 Jan 2023 | 9633.3 µg/m³ | – |
| 6 Jan 2024 | 9633.3 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 7 Jan 2024 | 9432.0 µg/m³ | Southern Norway, 5 to 10 January 2024 |
| 13 Jan 2024 | 9030.1 µg/m³ | Southern Norway, 12 to 13 January 2024 |
| 4 Jan 2025 | 8728.6 µg/m³ | Southern Norway, 4 January 2025 |
| 19 Jan 2024 | 8527.1 µg/m³ | Southern Norway, 18 to 20 January 2024 |
| 7 Mar 2025 | 8527.1 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
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, Oslo, Norway, 1 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/no/oslo/history (accessed 12 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.
Oslo now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 18:07 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).