Visalia Air Quality in Winter
Across 2019–2025, Visalia's winter (December–February) air quality had a median AQI of 63 (Moderate) over 632 monitored days in the Visalia-Porterville, CA area. 9.7% of winter days (61 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 85.4% of days. The cleanest winter on record here was 2025 (median AQI 63, 1 day above 100) and the worst was 2021 (median 62, 15 days above 100, peak AQI 157).
- Good: 22.8%
- Moderate: 67.6%
- Unhealthy for Sensitive Groups: 8.4%
- Unhealthy or worse: 1.3%
Extra Protection for Visalia Homes
Air quality in Visalia is moderate (AQI 66), 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 Visalia in winter?
Moderate on a typical day: median AQI 63 across 2019–2025, with 9.7% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓22.8% of winter days were Good (AQI 0–50), 67.6% Moderate (51–100).
- ✓61 days of 632 reached AQI 101+; the winter peak was 158.
- ✓Cleanest month: February; worst month: December.
Frequently asked questions
What is the air quality like in Visalia in winter?▾
Across 2019–2025, the median daily AQI in Visalia in winter was 63 (Moderate). 22.8% of days were Good, 67.6% Moderate, and 9.7% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Visalia?▾
A typical winter day in Visalia is Moderate (median AQI 63): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 10 of winter days (9.7%) 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 winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 85.4% of winter days in Visalia. The highest winter AQI recorded in 2019–2025 was 158 (Unhealthy), in 2021.
Visalia winter air quality, year by year
Visalia winter air quality by year (Visalia-Porterville, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 90 | 54 | 6 | 138 | PM2.5 |
| 2020 | 91 | 71 | 11 | 129 | PM2.5 |
| 2021worst | 90 | 62 | 15 | 157 | PM2.5 |
| 2022 | 90 | 75 | 12 | 158 | PM2.5 |
| 2023 | 90 | 58 | 7 | 119 | PM2.5 |
| 2024 | 91 | 60 | 9 | 157 | PM2.5 |
| 2025cleanest | 90 | 63 | 1 | 104 | PM2.5 |
What winter air means in Visalia
A typical winter day in Visalia is Moderate (median AQI 63): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 10 of winter days (9.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Winter's median AQI of 63 is below Visalia's whole-year median of 71, making it one of the area's cleaner periods. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Visalia runs above the national Winter norm; 9.7% of its Winter days topped AQI 100 versus 0.6% nationally (above average).
Within the season, February is the cleanest month (median AQI 57, 1.0% of days above 100) and December the worst (median 66, 14.3% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Visalia
The latest EPA AirNow observation puts Visalia's AQI at 66 (PM2.5). The figures above are multi-year season 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.