Today | Weather | Wednesday, December 10, 2025

Weather in Ontario, California

12:11 PM
Now
Sunny Weather
81° F
Feels Like 81°
Precipitation 0 %
Wind 7 mph
UV Index (0 - 11+) 3
Humidity 17 %
Today
Sunny Weather
Day 82°
Night 52°
Precipitation 0 %
Wind 6 mph
UV Index (0 - 11+) 3

Ontario Weather Forecast Updated

42 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (December 10, 2024)
Cloudy Night

Day

68°

Night

45°

Wind

6 mph

Precipitation

0 %

Air Quality in Ontario

NOW
160 AQI
Unhealthy air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 74.54 µg/m³
PM10 89.21 µg/m³
O3 0.040 ppm
NO2 31.4 ppb
SO2 1.2 ppb
CO 0.68 ppm
NH3 0.52 µg/m³
NO 13.5 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:

Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.

Show raw pollutant concentrations (µg/m³)
PM2.574.54 µg/m³
PM1089.21 µg/m³
O379.23 µg/m³
NO259.03 µg/m³
SO23.24 µg/m³
CO776.72 µg/m³
NH30.52 µg/m³
NO13.5 µg/m³