Riverside Air Quality in March

Across 2019–2025, Riverside's March air quality had a median AQI of 61 (Moderate) over 217 monitored days in the Riverside-San Bernardino-Ontario, CA area. 5.9% of March days (13 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 42.9% of days. The cleanest March on record here was 2020 (median AQI 54, 0 days above 100) and the worst was 2025 (median 64, 6 days above 100, peak AQI 174).

61
Median AQI
Moderate
5.9%
Days above AQI 100
13 of 217 days
88
90th percentile AQI
worst 1 day in 10
196
Peak AQI
Unhealthy
O3
Main pollutant
42.9% of days
18.9%
Good days
41 of 217
  • Good: 18.9%
  • Moderate: 75.1%
  • Unhealthy for Sensitive Groups: 4.1%
  • Unhealthy or worse: 1.8%

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QUICK ANSWER

How is the air in Riverside in March?

Moderate on a typical day: median AQI 61 across 2019–2025, with 5.9% of March days above AQI 100. Ground-level ozone is the main driver.

  • 18.9% of March days were Good (AQI 0–50), 75.1% Moderate (51–100).
  • 13 days of 217 reached AQI 101+; the March peak was 196.
  • Best March: 2020; worst March: 2025.

Frequently asked questions

What is the air quality like in Riverside in March?

Across 2019–2025, the median daily AQI in Riverside in March was 61 (Moderate). 18.9% of days were Good, 75.1% Moderate, and 5.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is March a good time for outdoor exercise in Riverside?

A typical March day in Riverside is Moderate (median AQI 61): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 17 of March days (5.9%) 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 March air quality problems?

Ground-level ozone set the daily AQI on 42.9% of March days in Riverside. The highest March AQI recorded in 2019–2025 was 196 (Unhealthy), in 2025.

Riverside March air quality, year by year

Riverside March air quality by year (Riverside-San Bernardino-Ontario, CA, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931692150O3
2020cleanest3154086O3
202131653196PM2.5
202231622186O3
20233155078PM2.5
202431550100O3
2025worst31646174O3

What March air means in Riverside

A typical March day in Riverside is Moderate (median AQI 61): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 17 of March days (5.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

March's median AQI of 61 is below Riverside's whole-year median of 89, making it one of the area's cleaner periods. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so Riverside runs above the national March norm; 5.9% of its March days topped AQI 100 versus 0.4% nationally (above average).

March is part of Riverside's spring season (March, April, May); the spring 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 58 (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.