Visalia Air Quality in May
Across 2019–2025, Visalia's May air quality had a median AQI of 67 (Moderate) over 217 monitored days in the Visalia-Porterville, CA area. 15.2% of May days (33 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 83.9% of days. The cleanest May on record here was 2019 (median AQI 54, 0 days above 100) and the worst was 2020 (median 64, 7 days above 100, peak AQI 151).
- Good: 28.1%
- Moderate: 56.7%
- Unhealthy for Sensitive Groups: 14.7%
- Unhealthy or worse: 0.5%
Extra Protection for Visalia Homes
Air quality in Visalia is moderate (AQI 83), with particle pollution 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 May?
Moderate on a typical day: median AQI 67 across 2019–2025, with 15.2% of May days above AQI 100. Ground-level ozone is the main driver.
- ✓28.1% of May days were Good (AQI 0–50), 56.7% Moderate (51–100).
- ✓33 days of 217 reached AQI 101+; the May peak was 151.
- ✓Best May: 2019; worst May: 2020.
Frequently asked questions
What is the air quality like in Visalia in May?▾
Across 2019–2025, the median daily AQI in Visalia in May was 67 (Moderate). 28.1% of days were Good, 56.7% Moderate, and 15.2% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is May a good time for outdoor exercise in Visalia?▾
A typical May 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 7 of May days (15.2%) 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 May air quality problems?▾
Ground-level ozone set the daily AQI on 83.9% of May days in Visalia. The highest May AQI recorded in 2019–2025 was 151 (Unhealthy), in 2020.
Visalia May air quality, year by year
Visalia May air quality by year (Visalia-Porterville, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 54 | 0 | 93 | O3 |
| 2020worst | 31 | 64 | 7 | 151 | O3 |
| 2021 | 31 | 77 | 5 | 133 | O3 |
| 2022 | 31 | 71 | 5 | 143 | O3 |
| 2023 | 31 | 67 | 5 | 129 | O3 |
| 2024 | 31 | 74 | 6 | 133 | O3 |
| 2025 | 31 | 71 | 5 | 140 | O3 |
What May air means in Visalia
A typical May 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 7 of May days (15.2%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
May'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 May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Visalia runs above the national May norm; 15.2% of its May days topped AQI 100 versus 1.3% nationally (above average).
May is part of Visalia's spring season (March, April, May); the spring 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.