Salt Lake City Air Quality in December
Across 2019–2025, Salt Lake City's December air quality had a median AQI of 54 (Moderate) over 217 monitored days in the Salt Lake City, UT area. 6.9% of December days (15 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 66.4% of days. The cleanest December on record here was 2025 (median AQI 48, 0 days above 100) and the worst was 2024 (median 52, 5 days above 100, peak AQI 126).
- Good: 42.9%
- Moderate: 50.2%
- Unhealthy for Sensitive Groups: 6.9%
- Unhealthy or worse: 0.0%
Extra Protection for Salt Lake City Homes
Air quality in Salt Lake City is moderate (AQI 52), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How is the air in Salt Lake City in December?
Moderate on a typical day: median AQI 54 across 2019–2025, with 6.9% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓42.9% of December days were Good (AQI 0–50), 50.2% Moderate (51–100).
- ✓15 days of 217 reached AQI 101+; the December peak was 149.
- ✓Best December: 2025; worst December: 2024.
Frequently asked questions
What is the air quality like in Salt Lake City in December?▾
Across 2019–2025, the median daily AQI in Salt Lake City in December was 54 (Moderate). 42.9% of days were Good, 50.2% Moderate, and 6.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is December a good time for outdoor exercise in Salt Lake City?▾
A typical December day in Salt Lake City is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of December days (6.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Salt Lake City's December air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 66.4% of December days in Salt Lake City. The highest December AQI recorded in 2019–2025 was 149 (Unhealthy for Sensitive Groups), in 2024.
Salt Lake City December air quality, year by year
Salt Lake City December air quality by year (Salt Lake City, UT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 56 | 3 | 136 | PM2.5 |
| 2020 | 31 | 55 | 1 | 106 | PM2.5 |
| 2021 | 31 | 42 | 3 | 149 | PM2.5 |
| 2022 | 31 | 55 | 3 | 128 | PM2.5 |
| 2023 | 31 | 63 | 0 | 100 | PM2.5 |
| 2024worst | 31 | 52 | 5 | 126 | PM2.5 |
| 2025cleanest | 31 | 48 | 0 | 88 | PM2.5 |
What December air means in Salt Lake City
A typical December day in Salt Lake City is Moderate (median AQI 54): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of December days (6.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
December's median AQI of 54 is in line with Salt Lake City's whole-year median of 57, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median December AQI across every EPA metro area (95,590 metro-days, 2019–2025) is 39, so Salt Lake City runs above the national December norm; 6.9% of its December days topped AQI 100 versus 0.7% nationally (above average).
December is part of Salt Lake City's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Salt Lake City
The latest EPA AirNow observation puts Salt Lake City's AQI at 52 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Salt Lake City air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Salt Lake City, UT), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.