SmogRank / United States / Wyoming / Ranchettes

Ranchettes, month by month

Ranchettes has a measured daily mean on 1,256 days since 5 January 2023. Its worst month was May 2023, at 56 US AQI (11.8 µg/m³), 279th of 1,600 cities on that month's world ranking. Its cleanest was December 2025, at 9 US AQI (1.6 µg/m³). 2025 averaged 18 US AQI (3.2 µg/m³), against 23 US AQI (4.1 µg/m³) in 2024.

Every month since 2023

202618 so far277 days measured2,781st of 2,791 in the world
Jan12#2,610Feb11#2,856Mar14#2,950Apr13#2,924May11#2,865Jun18#2,401Jul29#2,567Aug39#2,099Sep13#2,959Oct17#2,649
202518 for the year354 days measured2,670th of 2,681 in the world
Jan15#2,456Feb26#2,429Mar19#2,742Apr15#2,930May13#2,809Jun21#2,435Jul23#2,754Aug24#2,776Sep27#2,690Oct12#2,606Nov12#2,703Dec9#3,002
202423 for the year352 days measured2,041st of 2,097 in the world
Jan18#2,326Feb17#2,421Mar19#1,578Apr26#2,089May21#2,478Jun18#2,462Jul46#1,233Aug22#1,964Sep21#1,944Oct37#1,271Nov14#2,590Dec14#2,589
202331 for the year273 days measured1,214th of 1,355 in the world
Jan12 daysFeb1 dayMar10 daysApr15 daysMay56#279Jun34#1,312Jul34#1,065Aug32#1,683Sep28#1,967Oct22#1,918Nov20#2,165Dec18#2,190
Each square is a month's mean PM2.5 in US AQI from Ranchettes's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Ranchettes marked; each year, the year's. A dashed square is the running month, so far.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

4 months
MonthWhy
Apr 202315 of 30 days measured; a month needs 21. The others: 3 missing from OpenAQ's archive, 12 with under 18 hours of readings or readings that failed our checks.
Mar 202310 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 20231 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.
Jan 202312 of 31 days measured; a month needs 22. The others: 7 missing from OpenAQ's archive, 8 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.

Ranchettes's worst months

MonthUS AQIDays measuredWorld rankEpisode
May 2023 5611.8 µg/m³28 of 31279thof 1,600North-western United States and Canada, May 2023
Northern United States and Canada, May 2023
July 2024 468.3 µg/m³29 of 311,233rdof 2,566North-western United States and Canada, July 2024
August 2026 397.0 µg/m³31 of 312,099thof 2,896–
October 2024 376.6 µg/m³30 of 311,271stof 2,020–
July 2023 346.2 µg/m³25 of 311,065thof 1,432–
June 2023 346.1 µg/m³30 of 301,312thof 1,603–

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.

Ranchettes's worst days

DayUS AQIEpisode
19 May 2023 15763.8 µg/m³North-western United States and Canada, May 2023
Northern United States and Canada, May 2023
20 May 2023 9935.1 µg/m³North-western United States and Canada, May 2023
4 Sept 2025 8929.5 µg/m³Colorado and Wyoming, United States, September 2025
18 May 2023 8829.0 µg/m³Northern United States and Canada, May 2023
23 Jul 2024 8527.3 µg/m³North-western United States and Canada, July 2024
22 May 2023 8527.2 µg/m³North-western United States and Canada, May 2023
24 Jul 2024 7924.3 µg/m³North-western United States and Canada, July 2024
12 Mar 2026 7622.6 µg/m³–
22 Jul 2024 7522.1 µg/m³North-western United States and Canada, July 2024
21 May 2023 7320.8 µg/m³North-western United States and Canada, May 2023

Daily means, the highest since 5 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, Ranchettes, United States, 5 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/ranchettes/history (accessed 12 Oct 2026).

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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.

Ranchettes now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 17:07 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).