SmogRank / Canada / British Columbia / North Cowichan
North Cowichan, month by month
North Cowichan has a measured daily mean on 1,187 days since 1 January 2023. Its worst month was November 2023, at 36 US AQI (6.5 µg/m³), 1,566th of 2,243 cities on that month's world ranking. Its cleanest was May 2025, at 11 US AQI (2.0 µg/m³). 2025 averaged 22 US AQI (3.9 µg/m³), against 19 US AQI (3.5 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
5 months
| Month | Why |
|---|---|
| Nov 2025 | 20 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 17 of 28 days measured; a month needs 20. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Apr 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 2023 | 10 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 2 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.
North Cowichan's worst months
| Month | US AQI | World rank |
|---|---|---|
| November 2023 | 366.5 µg/m³ | 1,566thof 2,243 |
| August 2023 | 356.3 µg/m³ | 1,561stof 1,980 |
| January 2025 | 346.1 µg/m³ | 1,955thof 2,474 |
| September 2025 | 315.6 µg/m³ | 2,285thof 3,104 |
| January 2026 | 315.5 µg/m³ | 2,250thof 2,617 |
| October 2023 | 295.3 µg/m³ | 1,696thof 2,012 |
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.
North Cowichan's worst days
| Day | US AQI |
|---|---|
| 27 Aug 2023 | 7723.0 µg/m³ |
| 26 Aug 2023 | 7421.6 µg/m³ |
| 21 Oct 2023 | 7220.5 µg/m³ |
| 25 Aug 2023 | 7119.7 µg/m³ |
| 27 Nov 2023 | 6818.1 µg/m³ |
| 20 Aug 2023 | 6717.6 µg/m³ |
| 22 Jul 2026 | 6114.3 µg/m³ |
| 1 Nov 2023 | 6114.2 µg/m³ |
| 3 Sept 2025 | 6013.8 µg/m³ |
| 28 Nov 2023 | 6013.7 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, North Cowichan, Canada, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/ca/north-cowichan/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.
North Cowichan now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 22:07 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).