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Today | Weather | Thursday, March 12, 2026
Active Weather Warnings

Weather in Fontana, California

07:36 AM
Now
Sunny Weather
61° F
Feels Like 61°
Precipitation 0 %
Wind 7 mph
UV Index (0 - 11+) 1
Humidity 46 %
Today
Sunny Weather
Day 91°
Night 61°
Precipitation 0 %
Wind 8 mph
UV Index (0 - 11+) 6

Fontana Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (March 12, 2025)
Rainy Weather

Day

63°

Night

50°

Wind

9 mph

UV Index

2

Precipitation

89 %

Air Quality in Fontana

NOW
73 AQI
Moderate air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 22.77 µg/m³
PM10 31.1 µg/m³
O3 0.032 ppm
NO2 6.4 ppb
SO2 0.9 ppb
CO 0.24 ppm
NH3 0.32 µg/m³
NO 0.1 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 acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Show raw pollutant concentrations (µg/m³)
PM2.5 – 22.77 µg/m³
PM10 – 31.1 µg/m³
O3 – 63.04 µg/m³
NO2 – 12.09 µg/m³
SO2 – 2.44 µg/m³
CO – 269.31 µg/m³
NH3 – 0.32 µg/m³
NO – 0.1 µg/m³
View Hourly Air Quality Forecast

Weather Alerts and Warnings for Fontana

Moderate Expected Likely

Heat Advisory

Heat Advisory issued March 12 at 5:39AM PDT until March 13 at 8:00PM PDT by NWS San Diego CA
Mar 12, 10:00 AM → Mar 13, 8:00 PM
WHAT: High temperatures from the lower to mid 80s near the coast
and lower to mid 90s for the valleys and inland Orange County
expected.

WHERE: Orange County Coastal Areas, Orange County Inland Areas,
San Bernardino and Riverside County Valleys-The Inland Empire, San
Diego County Coastal Areas, and San Diego County Valleys.

WHEN: From 10 AM this morning to 8 PM PDT Friday.

IMPACTS: Hot temperatures may cause heat illnesses.
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Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
Updated: Mar 12, 5:54 AM Source: NWS Alert