Visalia Air Quality in January

Across 2019–2025, Visalia's January air quality had a median AQI of 67 (Moderate) over 217 monitored days in the Visalia-Porterville, CA area. 12.9% of January days (28 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 90.3% of days. The cleanest January on record here was 2023 (median AQI 47, 0 days above 100) and the worst was 2022 (median 82, 10 days above 100, peak AQI 158).

67
Median AQI
Moderate
12.9%
Days above AQI 100
28 of 217 days
110
90th percentile AQI
worst 1 day in 10
158
Peak AQI
Unhealthy
PM2.5
Main pollutant
90.3% of days
17.5%
Good days
38 of 217
  • Good: 17.5%
  • Moderate: 69.6%
  • Unhealthy for Sensitive Groups: 12.4%
  • Unhealthy or worse: 0.5%

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QUICK ANSWER

How is the air in Visalia in January?

Moderate on a typical day: median AQI 67 across 2019–2025, with 12.9% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 17.5% of January days were Good (AQI 0–50), 69.6% Moderate (51–100).
  • 28 days of 217 reached AQI 101+; the January peak was 158.
  • Best January: 2023; worst January: 2022.

Frequently asked questions

What is the air quality like in Visalia in January?

Across 2019–2025, the median daily AQI in Visalia in January was 67 (Moderate). 17.5% of days were Good, 69.6% Moderate, and 12.9% 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 Visalia?

A typical January day in Visalia is Moderate (median AQI 67): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of January days (12.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Visalia's January air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 90.3% of January days in Visalia. The highest January AQI recorded in 2019–2025 was 158 (Unhealthy), in 2022.

Visalia January air quality, year by year

Visalia January air quality by year (Visalia-Porterville, CA, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931616138PM2.5
202031691111PM2.5
202131769124PM2.5
2022worst318210158PM2.5
2023cleanest31470100PM2.5
202431571110PM2.5
202531691104PM2.5

What January air means in Visalia

A typical January day in Visalia is Moderate (median AQI 67): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 8 of January days (12.9%) 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 67 is below Visalia's whole-year median of 71, making it one of the area's cleaner periods. Nationally, the median January AQI across every EPA metro area (95,602 metro-days, 2019–2025) is 39, so Visalia runs above the national January norm; 12.9% of its January days topped AQI 100 versus 0.7% nationally (above average).

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

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

Right now in Visalia

The latest EPA AirNow observation puts Visalia's AQI at 83 (PM10). The figures above are multi-year month statistics, not today's reading.

View current Visalia air quality →

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