Modesto Air Quality in 2020
In 2020, Modesto's air quality (Modesto, CA area) had a median daily AQI of 60 (Moderate) across 366 monitored days. 37 days (10.1%) reached Unhealthy for Sensitive Groups or worse, 131 were Good, and the year's peak AQI was 195 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 182 of those days. The cleanest month of 2020 was March (median AQI 36, 0 days above 100) and the worst was September (median 92, 14 days above 100, peak 195).
- Good: 35.8%
- Moderate: 54.1%
- Unhealthy for Sensitive Groups: 5.7%
- Unhealthy or worse: 4.4%
Extra Protection for Modesto Homes
Air quality in Modesto is moderate (AQI 63), 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
As an Amazon Associate, we earn from qualifying purchases.
How was Modesto's air quality in 2020?
Moderate on a typical day: median AQI 60, with 37 days above AQI 100 out of 366 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2020: 195 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 182 days.
- ✓Cleanest month: March; worst: September.
Frequently asked questions
What was the average AQI in Modesto in 2020?▾
EPA's Air Quality System puts Modesto's (Modesto, CA) median daily AQI for 2020 at 60, which is Moderate. 37 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 195.
Which month had the worst air quality in Modesto in 2020?▾
The cleanest month of 2020 was March (median AQI 36, 0 days above 100) and the worst was September (median 92, 14 days above 100, peak 195).
Was 2020 a good or bad year for Modesto's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100. 2020's median of 60 is above the area's typical annual median of 54.
Modesto month by month in 2020
Modesto air quality month by month, 2020 (Modesto, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 64 | 0 | 91 | PM2.5 |
| February | 29 | 60 | 0 | 93 | PM2.5 |
| Marchcleanest | 31 | 36 | 0 | 68 | O3 |
| April | 30 | 41 | 0 | 51 | O3 |
| May | 31 | 45 | 1 | 105 | O3 |
| June | 30 | 47 | 0 | 93 | O3 |
| July | 31 | 61 | 1 | 103 | O3 |
| August | 31 | 74 | 11 | 188 | O3 |
| Septemberworst | 30 | 92 | 14 | 195 | PM2.5 |
| October | 31 | 74 | 4 | 173 | PM2.5 |
| November | 30 | 71 | 2 | 108 | PM2.5 |
| December | 31 | 80 | 4 | 108 | PM2.5 |
How 2020 compares
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100.
2020's median of 60 is above the area's typical annual median of 54.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Modesto
The latest EPA AirNow observation puts Modesto's AQI at 63 (PM10). The figures above are multi-year annual statistics, not today's reading.
View current Modesto air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Modesto, 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.