Bad Air Days in Weston County, Wyoming: under 1 a Year
under 1 bad air day a year
Fewer bad air days than most monitored US counties. Ranked 722 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (0% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in July and June and August. 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 Weston
The worst recent year was 2024, with 5 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2024-07-23 | 136 | Ozone |
| 2020-08-23 | 119 | Ozone |
| 2024-07-24 | 115 | Ozone |
| 2024-07-25 | 115 | Ozone |
| 2024-07-29 | 105 | Ozone |
Most days, not the worst ones
Across 3,117 monitored days from 2016 to 2024, the air in Weston County rated Good on 89% of them, more often than the 72% typical of monitored counties, and Moderate on 11%. The median day sat at AQI 41; one day in ten went above 53.
The pollutant setting the AQI on an ordinary day here:
- ozone100%3,110 days
Weston County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2024 | 365 | 320 | 40 | 5 | 0 | 39 | 136 |
| 2023 | 347 | 315 | 32 | 0 | 0 | 42 | 90 |
| 2022 | 363 | 344 | 19 | 0 | 0 | 40 | 64 |
| 2021 | 343 | 282 | 61 | 0 | 0 | 41 | 100 |
| 2020 | 353 | 323 | 29 | 1 | 0 | 40 | 119 |
| 2019 | 360 | 335 | 25 | 0 | 0 | 40 | 71 |
| 2018 | 340 | 291 | 48 | 1 | 0 | 42 | 101 |
| 2017 | 289 | 257 | 32 | 0 | 0 | 41 | 93 |
| 2016 | 357 | 314 | 43 | 0 | 0 | 42 | 80 |
| 2015 | 364 | 324 | 40 | 0 | 0 | 40 | 93 |
| 2014 | 356 | 322 | 34 | 0 | 0 | 41 | 77 |
| 2013 | 355 | 284 | 71 | 0 | 0 | 44 | 93 |
| 2012 | 43 | 43 | 0 | 0 | 0 | 37 | 44 |
Nearby counties on file
- Platte County9/yr
- Sweetwater County7/yr
- Albany County6/yr
- Campbell County5/yr
- Sublette County5/yr
- Sheridan County3/yr
- Laramie County3/yr
- Teton County3/yr
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.