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Today | Weather | Tuesday, October 21, 2025

Weather in Fontana, California

07:16 PM
Now
Cloudy Night
75° F
Feels Like 73°
Precipitation 9 %
Wind 8 mph
Humidity 45 %
Today
Partly Sunny with Showers
Day 88°
Night 61°
Precipitation 40 %
Wind 5 mph
UV Index (0 - 11+) 11

Warning: Extreme UV Index Today: 11+

Overexposure to the sun's harmful UV rays can cause sunburn and increase the risk of developing skin cancer, including melanoma. Protect yourself by wearing clothing that covers your skin, sunglasses, and a hat. Apply a broad-spectrum sunscreen with an SPF of 30 or higher every two hours, even on cloudy days. Minimize direct sun exposure during peak hours (10 AM to 4 PM) to reduce the risk.

Fontana Weather Forecast Updated

34 minutes ago
Last updated on

Weather Forecast History

Last Year's Weather on This Day (October 21, 2024)

Cloudy Night

Day

86°

Night

55°

Wind

4 mph

Precipitation

0

Air Quality in Fontana

NOW
42 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 8.13 µg/m³
PM10 19.05 µg/m³
O3 0.046 ppm
NO2 0.8 ppb
SO2 0.4 ppb
CO 0.09 ppm
NH3 0 µg/m³
NO 0 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)
PM2.5 – 8.13 µg/m³
PM10 – 19.05 µg/m³
O3 – 89.71 µg/m³
NO2 – 1.42 µg/m³
SO2 – 1 µg/m³
CO – 106.02 µg/m³
NH3 – 0 µg/m³
NO – 0 µg/m³
View Hourly Air Quality Forecast