Riverside Air Quality in January
Across 2019–2025, Riverside's January air quality had a median AQI of 64 (Moderate) over 217 monitored days in the Riverside-San Bernardino-Ontario, CA area. 6.9% of January days (15 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 59, 0 days above 100) and the worst was 2020 (median 72, 5 days above 100, peak AQI 207).
- Good: 10.6%
- Moderate: 82.5%
- Unhealthy for Sensitive Groups: 5.5%
- Unhealthy or worse: 1.4%
Extra Protection for Riverside Homes
Air quality in Riverside is moderate (AQI 56), 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 Riverside in January?
Moderate on a typical day: median AQI 64 across 2019–2025, with 6.9% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓10.6% of January days were Good (AQI 0–50), 82.5% Moderate (51–100).
- ✓15 days of 217 reached AQI 101+; the January peak was 365.
- ✓Best January: 2023; worst January: 2020.
Frequently asked questions
What is the air quality like in Riverside in January?▾
Across 2019–2025, the median daily AQI in Riverside in January was 64 (Moderate). 10.6% of days were Good, 82.5% Moderate, and 6.9% 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 Riverside?▾
A typical January day in Riverside is Moderate (median AQI 64): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of January days (6.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Riverside's January air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 90.3% of January days in Riverside. The highest January AQI recorded in 2019–2025 was 365 (Hazardous), in 2020.
Riverside January air quality, year by year
Riverside January air quality by year (Riverside-San Bernardino-Ontario, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 59 | 2 | 121 | PM2.5 |
| 2020worst | 31 | 72 | 5 | 207 | PM2.5 |
| 2021 | 31 | 66 | 1 | 133 | PM2.5 |
| 2022 | 31 | 73 | 1 | 112 | PM2.5 |
| 2023cleanest | 31 | 59 | 0 | 99 | PM2.5 |
| 2024 | 31 | 64 | 2 | 110 | PM2.5 |
| 2025 | 31 | 64 | 4 | 365 | PM2.5 |
What January air means in Riverside
A typical January day in Riverside is Moderate (median AQI 64): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of January days (6.9%) 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 64 is below Riverside's whole-year median of 89, 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 Riverside runs above the national January norm; 6.9% of its January days topped AQI 100 versus 0.7% nationally (above average).
January is part of Riverside's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Riverside
The latest EPA AirNow observation puts Riverside's AQI at 56 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Riverside air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Riverside-San Bernardino-Ontario, 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.