Bad Air Days in Uinta County, Wyoming: under 1 a Year

under 1 bad air day a year

Rare: among the cleanest-air counties EPA monitors. Ranked 772 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (33% particle days).

Which months to watch

Most bad days here fall in August and March and October and November. Averaged over 2016 to 2025.

What actually helps here

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

The record for Uinta

In 2000 to 2009 this county averaged 1 bad days a year; in 2016 to 2025, under 1. Not much has changed. The worst recent year was 2017, with 2 bad days on 365 monitored days.

Date	AQI	Main pollutant
2017-11-01	718	PM10
2020-08-21	122	Ozone
2020-08-22	119	Ozone
2017-10-07	109	PM10
2018-08-03	108	Ozone

Most days, not the worst ones

Across 3,487 monitored days from 2016 to 2025, the air in Uinta County rated Good on 93% of them, more often than the 72% typical of monitored counties, and Moderate on 7%. The median day sat at AQI 26; one day in ten went above 37.

The pollutant setting the AQI on an ordinary day here:

coarse dust (PM10)53%1,833 days
ozone47%1,646 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	269	269	0	0	0	9	50
2024	297	297	0	0	0	7	44
2023	365	365	0	0	0	6	32
2022	365	363	2	0	0	7	55
2021	364	361	3	0	0	7	60
2020	366	323	41	2	0	40	122
2019	365	315	49	1	0	44	101
2018	365	287	77	1	0	44	108
2017	365	310	53	2	1	44	718
2016	366	341	25	0	0	42	87
2015	365	316	47	2	0	41	101
2014	365	331	34	0	0	42	77
2013	365	312	53	0	0	44	93
2012	366	254	111	1	0	44	115
2011	365	322	43	0	0	43	90
2010	364	286	76	2	0	44	135

*2025 may be a partial year in EPA's file.

Wyoming compared

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.