Stockton Air Quality in October
Across 2019–2025, Stockton's October air quality had a median AQI of 54 (Moderate) over 217 monitored days in the Stockton-Lodi, CA area. 4.1% of October days (9 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 57.6% of days. The cleanest October on record here was 2025 (median AQI 42, 0 days above 100) and the worst was 2020 (median 71, 5 days above 100, peak AQI 181).
- Good: 40.6%
- Moderate: 55.3%
- Unhealthy for Sensitive Groups: 2.3%
- Unhealthy or worse: 1.8%
Extra Protection for Stockton Homes
Air quality in Stockton is moderate (AQI 60), 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 Stockton in October?
Moderate on a typical day: median AQI 54 across 2019–2025, with 4.1% of October days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓40.6% of October days were Good (AQI 0–50), 55.3% Moderate (51–100).
- ✓9 days of 217 reached AQI 101+; the October peak was 190.
- ✓Best October: 2025; worst October: 2020.
Frequently asked questions
What is the air quality like in Stockton in October?▾
Across 2019–2025, the median daily AQI in Stockton in October was 54 (Moderate). 40.6% of days were Good, 55.3% Moderate, and 4.1% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Stockton?▾
A typical October day in Stockton 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 24 of October days (4.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Stockton's October air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 57.6% of October days in Stockton. The highest October AQI recorded in 2019–2025 was 190 (Unhealthy), in 2020.
Stockton October air quality, year by year
Stockton October air quality by year (Stockton-Lodi, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 55 | 1 | 190 | PM2.5 |
| 2020worst | 31 | 71 | 5 | 181 | PM2.5 |
| 2021 | 31 | 52 | 2 | 124 | PM2.5 |
| 2022 | 31 | 52 | 0 | 69 | PM2.5 |
| 2023 | 31 | 51 | 0 | 90 | PM2.5 |
| 2024 | 31 | 52 | 1 | 140 | PM2.5 |
| 2025cleanest | 31 | 42 | 0 | 65 | PM2.5 |
What October air means in Stockton
A typical October day in Stockton 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 24 of October days (4.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
October's median AQI of 54 is above Stockton's whole-year median of 48, making it one of the area's dirtier periods. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Stockton runs above the national October norm; 4.1% of its October days topped AQI 100 versus 1.3% nationally (above average).
October is part of Stockton's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Stockton
The latest EPA AirNow observation puts Stockton's AQI at 60 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Stockton air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Stockton-Lodi, 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.