Today | Weather | Saturday, May 16, 2026

Weather in Ontario, California

04:16 PM
Now
Cloudy Weather
72° F
Feels Like 72°
Precipitation 0 %
Wind 16 mph
UV Index (0 - 11+) 5
Humidity 56 %
Today
Cloudy Weather
Day 72°
Night 55°
Precipitation 4 %
Wind 10 mph
UV Index (0 - 11+) 5

Ontario Weather Forecast Updated

33 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (May 16, 2025)
Cloudy Weather

Day

75°

Night

55°

Wind

7 mph

UV Index

11

Precipitation

1 %

Air Quality in Ontario

NOW
46 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 6.15 µg/m³
PM10 18.73 µg/m³
O3 0.050 ppm
NO2 0.1 ppb
SO2 0.3 ppb
CO 0.11 ppm
NH3 0.01 µg/m³
NO 0.04 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.56.15 µg/m³
PM1018.73 µg/m³
O398.03 µg/m³
NO20.23 µg/m³
SO20.69 µg/m³
CO120.4 µg/m³
NH30.01 µg/m³
NO0.04 µg/m³