SmogRank / United States / Wyoming / Riverton
Riverton, month by month
Riverton has a measured daily mean on 803 days since 1 January 2023. Its worst month was August 2026, at 52 US AQI (9.7 µg/m³), 969th of 2,896 cities on that month's world ranking. Its cleanest was May 2026, at 13 US AQI (2.3 µg/m³).
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
19 months
| Month | Why |
|---|---|
| Apr 2025 | 13 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | No day measured. The others: 31 with no readings from the monitor. |
| Nov 2024 | No day measured. The others: 30 with no readings from the monitor. |
| Oct 2024 | No day measured. The others: 31 with no readings from the monitor. |
| Sep 2024 | No day measured. The others: 30 with no readings from the monitor. |
| Aug 2024 | No day measured. The others: 31 with no readings from the monitor. |
| Jul 2024 | No day measured. The others: 31 with no readings from the monitor. |
| Jun 2024 | No day measured. The others: 30 with no readings from the monitor. |
| May 2024 | No day measured. The others: 31 with no readings from the monitor. |
| Apr 2024 | No day measured. The others: 30 with no readings from the monitor. |
| Mar 2024 | No day measured. The others: 30 with no readings from the monitor, 1 missing from OpenAQ's archive. |
| Feb 2024 | No day measured. The others: 28 with no readings from the monitor, 1 missing from OpenAQ's archive. |
| Jan 2024 | 1 of 31 days measured; a month needs 22. The others: 29 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours). |
| Mar 2023 | 10 of 31 days measured; a month needs 22. The others: 1 with readings for part of the day (a day needs 18 hours), 20 missing from OpenAQ's archive. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 1 with readings for part of the day (a day needs 18 hours), 25 missing from OpenAQ's archive. |
| Jan 2023 | 21 of 31 days measured; a month needs 22. The others: 4 with readings for part of the day (a day needs 18 hours), 6 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Riverton's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2026 | 529.7 µg/m³ | 969thof 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 | 376.6 µg/m³ | 1,203rdof 1,600 | North-western United States and Canada, May 2023 Northern United States and Canada, May 2023 |
| July 2025 | 315.5 µg/m³ | 2,486thof 2,889 | – |
| September 2025 | 315.5 µg/m³ | 2,344thof 3,104 | – |
| August 2025 | 285.0 µg/m³ | 2,697thof 2,901 | – |
| July 2023 | 264.7 µg/m³ | 1,274thof 1,432 | – |
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.
Riverton's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 May 2023 | 10537.3 µg/m³ | Northern United States and Canada, May 2023 |
| 19 May 2023 | 10135.7 µg/m³ | North-western United States and Canada, May 2023 Northern United States and Canada, May 2023 |
| 3 Aug 2026 | 9331.4 µg/m³ | North-western United States and Canada, July and August 2026 |
| 9 Aug 2026 | 8125.0 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 8 Aug 2026 | 7522.2 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 4 Sept 2025 | 7421.2 µg/m³ | – |
| 7 Aug 2026 | 7321.0 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 10 Aug 2026 | 7320.7 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
| 8 Jan 2023 | 7120.1 µg/m³ | – |
| 6 Aug 2026 | 7119.6 µg/m³ | North-western United States and Canada, 4 to 22 August 2026 |
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, Riverton, 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/riverton-wyoming/history (accessed 13 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.
Riverton now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 03:07 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).