Tucson Air Quality in January

Across 2019–2025, Tucson's January air quality had a median AQI of 51 (Moderate) over 217 monitored days in the Tucson, AZ area. 2.3% of January days (5 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 67.7% of days. The cleanest January on record here was 2019 (median AQI 40, 0 days above 100) and the worst was 2025 (median 61, 3 days above 100, peak AQI 251).

51
Median AQI
Moderate
2.3%
Days above AQI 100
5 of 217 days
63
90th percentile AQI
worst 1 day in 10
251
Peak AQI
Very Unhealthy
PM2.5
Main pollutant
67.7% of days
47.5%
Good days
103 of 217
  • Good: 47.5%
  • Moderate: 50.2%
  • Unhealthy for Sensitive Groups: 1.8%
  • Unhealthy or worse: 0.5%

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QUICK ANSWER

How is the air in Tucson in January?

Moderate on a typical day: median AQI 51 across 2019–2025, with 2.3% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 47.5% of January days were Good (AQI 0–50), 50.2% Moderate (51–100).
  • 5 days of 217 reached AQI 101+; the January peak was 251.
  • Best January: 2019; worst January: 2025.

Frequently asked questions

What is the air quality like in Tucson in January?

Across 2019–2025, the median daily AQI in Tucson in January was 51 (Moderate). 47.5% of days were Good, 50.2% Moderate, and 2.3% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is January a good time for outdoor exercise in Tucson?

A typical January day in Tucson is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 43 of January days (2.3%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Tucson's January air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 67.7% of January days in Tucson. The highest January AQI recorded in 2019–2025 was 251 (Very Unhealthy), in 2025.

Tucson January air quality, year by year

Tucson January air quality by year (Tucson, AZ, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
2019cleanest3140053PM2.5
20203141081O3
202131582128PM2.5
20223152071PM2.5
20233151063PM2.5
20243146083PM2.5
2025worst31613251PM2.5

What January air means in Tucson

A typical January day in Tucson is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 43 of January days (2.3%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

January's median AQI of 51 is in line with Tucson's whole-year median of 54, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median January AQI across every EPA metro area (95,602 metro-days, 2019–2025) is 39, so Tucson runs above the national January norm; 2.3% of its January days topped AQI 100 versus 0.7% nationally (above average).

January is part of Tucson's winter season (December, January, February); the winter page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Tucson

The latest EPA AirNow observation puts Tucson's AQI at 35 (O3). The figures above are multi-year month statistics, not today's reading.

View current Tucson air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Tucson, AZ), 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.