SmogRank / United States / Illinois / Joliet
Joliet, month by month
Joliet has a measured daily mean on 1,346 days since 1 January 2023. Its worst month was June 2023, at 93 US AQI (31.6 µg/m³), 69th of 1,603 cities on that month's world ranking. Its cleanest was April 2024, at 31 US AQI (5.5 µg/m³). 2025 averaged 51 US AQI (9.1 µg/m³), against 44 US AQI (7.9 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
1 month
| Month | Why |
|---|---|
| Mar 2024 | 12 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 18 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.
Joliet's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| June 2023 | 9331.6 µg/m³ | 69thof 1,603 | Eastern United States and Canada, June and July 2023 North-eastern United States, June 2023and 2 more |
| July 2026 | 7019.3 µg/m³ | 362ndof 2,784 | Northern United States and Canada, July 2026 |
| June 2025 | 6516.7 µg/m³ | 326thof 2,508 | Northern United States and Canada, June 2025 Northern United States and Canada, May and June 2025 |
| July 2023 | 6315.5 µg/m³ | 131stof 1,432 | Northern United States and Canada, July 2023 United States and Canada, July 2023and 1 more |
| July 2025 | 6014.0 µg/m³ | 509thof 2,889 | North-eastern United States and Canada, 29 July to 9 August 2025 Northern United States, July 2025and 1 more |
| August 2023 | 6013.9 µg/m³ | 229thof 1,980 | – |
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.
Joliet's worst days
| Day | US AQI | Episode |
|---|---|---|
| 28 Jun 2023 | 245170.0 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 27 Jun 2023 | 219144.0 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 17 Jul 2026 | 205130.0 µg/m³ | Northern United States and Canada, July 2026 |
| 16 Jul 2026 | 17589.1 µg/m³ | Northern United States and Canada, July 2026 |
| 29 Jun 2023 | 15966.3 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 31 Jul 2025 | 15460.4 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 16 Jul 2023 | 15257.5 µg/m³ | United States and Canada, July 2023 |
| 19 Jul 2026 | 14653.9 µg/m³ | Northern United States and Canada, July 2026 |
| 1 Aug 2025 | 14051.4 µg/m³ | North-eastern United States and Canada, 29 July to 9 August 2025 |
| 25 Jul 2023 | 13248.1 µg/m³ | Northern United States and Canada, July 2023 |
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, Joliet, United States, 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/us/joliet/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.
Joliet 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).