SmogRank / United States / Wyoming / Sheridan
Sheridan, month by month
Sheridan has a measured daily mean on 1,112 days since 1 January 2023. Its worst month was October 2024, at 77 US AQI (22.9 µg/m³), 74th of 2,020 cities on that month's world ranking. Its cleanest was May 2024, at 14 US AQI (2.5 µg/m³). 2025 averaged 29 US AQI (5.2 µg/m³), against 48 US AQI (8.6 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
10 months
| Month | Why |
|---|---|
| Jun 2026 | 17 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Mar 2026 | 17 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Apr 2024 | 15 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 1 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | 1 of 29 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2024 | No day measured. The others: 31 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 | 16 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 10 of 31 days measured; a month needs 22. The others: 21 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.
Sheridan's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| October 2024 | 7722.9 µg/m³ | 74thof 2,020 | North-western United States, October 2024 |
| July 2024 | 6717.5 µg/m³ | 128thof 2,566 | North-western United States and Canada, July 2024 |
| August 2026 | 6114.7 µg/m³ | 397thof 2,896 | North-western United States and Canada, 4 to 22 August 2026 North-western United States and Canada, July and August 2026 |
| May 2023 | 5611.7 µg/m³ | 287thof 1,600 | North-western United States and Canada, May 2023 Northern United States and Canada, May 2023 |
| January 2023 | 5310.3 µg/m³ | 447thof 1,261 | – |
| July 2026 | 529.5 µg/m³ | 1,493rdof 2,784 | North-western United States and Canada, July and August 2026 |
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.
Sheridan's worst days
| Day | US AQI | Episode |
|---|---|---|
| 14 Jul 2024 | 220145.0 µg/m³ | – |
| 5 Sept 2023 | 17691.5 µg/m³ | Northern United States and Canada, August and September 2023 |
| 6 Oct 2024 | 17184.4 µg/m³ | North-western United States, October 2024 |
| 10 Oct 2024 | 16169.9 µg/m³ | – |
| 14 Oct 2024 | 15865.7 µg/m³ | – |
| 15 Oct 2024 | 15763.5 µg/m³ | – |
| 12 Oct 2024 | 15460.4 µg/m³ | – |
| 8 Oct 2024 | 15155.7 µg/m³ | North-western United States, October 2024 |
| 9 Oct 2024 | 14352.6 µg/m³ | – |
| 7 Oct 2024 | 12344.5 µg/m³ | North-western United States, October 2024 |
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, Sheridan, 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/sheridan/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.
Sheridan now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 21:07 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).