Riverside Air Quality in Summer

Across 2019–2025, Riverside's summer (June–August) air quality had a median AQI of 154 (Unhealthy) over 644 monitored days in the Riverside-San Bernardino-Ontario, CA area. 87.3% of summer days (562 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 95.2% of days. The cleanest summer on record here was 2023 (median AQI 147, 67 days above 100) and the worst was 2021 (median 160, 85 days above 100, peak AQI 216).

154
Median AQI
Unhealthy
87.3%
Days above AQI 100
562 of 644 days
201
90th percentile AQI
worst 1 day in 10
584
Peak AQI
Hazardous
O3
Main pollutant
95.2% of days
0.2%
Good days
1 of 644
  • Good: 0.2%
  • Moderate: 12.6%
  • Unhealthy for Sensitive Groups: 32.8%
  • Unhealthy or worse: 54.5%

Extra Protection for Riverside Homes

Air quality in Riverside is moderate (AQI 58), 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.

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QUICK ANSWER

How is the air in Riverside in summer?

Unhealthy on a typical day: median AQI 154 across 2019–2025, with 87.3% of summer days above AQI 100. Ground-level ozone is the main driver.

  • 0.2% of summer days were Good (AQI 0–50), 12.6% Moderate (51–100).
  • 562 days of 644 reached AQI 101+; the summer peak was 584.
  • Cleanest month: June; worst month: July.

Frequently asked questions

What is the air quality like in Riverside in summer?

Across 2019–2025, the median daily AQI in Riverside in summer was 154 (Unhealthy). 0.2% of days were Good, 12.6% Moderate, and 87.3% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.

Is summer a good time for outdoor exercise in Riverside?

A typical summer day in Riverside is Unhealthy (median AQI 154): everyone should limit prolonged outdoor exertion, and sensitive groups should avoid it; about 87% of summer days (87.3%) were at AQI 101+.

Which pollutant causes Riverside's summer air quality problems?

Ground-level ozone set the daily AQI on 95.2% of summer days in Riverside. The highest summer AQI recorded in 2019–2025 was 584 (Hazardous), in 2021.

Riverside summer air quality, year by year

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

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20199215585213O3
20209215485584O3
2021worst9216085216O3
20229215182218O3
2023cleanest9214767517O3
20249216481227O3
20259214777207O3

What summer air means in Riverside

A typical summer day in Riverside is Unhealthy (median AQI 154): everyone should limit prolonged outdoor exertion, and sensitive groups should avoid it; about 87% of summer days (87.3%) were at AQI 101+.

Summer's median AQI of 154 is above Riverside's whole-year median of 89, making it one of the area's dirtier periods. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so Riverside runs above the national Summer norm; 87.3% of its Summer days topped AQI 100 versus 3.6% nationally (above average).

Within the season, June is the cleanest month (median AQI 142, 77.7% of days above 100) and July the worst (median 161, 94.1% above 100).

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 season 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.