Bad Air Days in Platte County, Wyoming: 9 a Year
9 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 103 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly particles: smoke and dust (100% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in December and February and January. Averaged over 2016 to 2025.
Is a purifier worth it here?
- Particles (wildfire smoke, dust) cause enough bad days here to matter. A HEPA purifier sized to your bedroom removes them; run it with windows shut on bad days.
- Upgrade the furnace or AC filter to MERV 13 so the whole house is filtered, not just one room.
The record for Platte
The worst recent year was 2022, with 15 bad days on 355 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2024-12-15 | 927 | PM10 |
| 2025-12-09 | 723 | PM10 |
| 2025-12-17 | 723 | PM10 |
| 2022-01-31 | 692 | PM10 |
| 2021-03-29 | 682 | PM10 |
Most days, not the worst ones
Across 2,270 monitored days from 2016 to 2025, the air in Platte County rated Good on 90% of them, more often than the 72% typical of monitored counties, and Moderate on 8%. The median day sat at AQI 16; one day in ten went above 50.
The pollutant setting the AQI on an ordinary day here:
- coarse dust (PM10)100%2,270 days
Platte County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 361 | 327 | 22 | 12 | 9 | 15 | 723 |
| 2024 | 366 | 325 | 32 | 9 | 3 | 19 | 927 |
| 2023 | 364 | 334 | 25 | 5 | 4 | 14 | 320 |
| 2022 | 355 | 311 | 29 | 15 | 7 | 17 | 692 |
| 2021 | 362 | 324 | 28 | 10 | 8 | 16 | 682 |
| 2020 | 224 | 202 | 20 | 2 | 1 | 19 | 283 |
| 2019 | 60 | 56 | 3 | 1 | 0 | 14 | 108 |
| 2018 | 61 | 58 | 3 | 0 | 0 | 15 | 55 |
| 2017 | 60 | 54 | 6 | 0 | 0 | 15 | 72 |
| 2016 | 57 | 50 | 7 | 0 | 0 | 16 | 66 |
| 2015 | 60 | 57 | 3 | 0 | 0 | 14 | 86 |
| 2014 | 60 | 58 | 2 | 0 | 0 | 17 | 88 |
| 2013 | 58 | 56 | 2 | 0 | 0 | 14 | 59 |
| 2012 | 61 | 57 | 4 | 0 | 0 | 17 | 86 |
| 2011 | 61 | 58 | 3 | 0 | 0 | 16 | 58 |
| 2010 | 61 | 59 | 2 | 0 | 0 | 12 | 59 |
*2025 may be a partial year in EPA's file.
Elsewhere in Wyoming
- Sweetwater County7/yr
- Albany County6/yr
- Campbell County5/yr
- Sublette County5/yr
- Sheridan County3/yr
- Laramie County3/yr
- Teton County3/yr
- Fremont County2/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.