Today | Weather | Sunday, August 9, 2026

Active Weather Warnings

Heat Advisory

Weather in Fontana, California

04:36 PM

Now

99° F

Feels Like 99°

Precipitation 0 %

Wind 13 mph

UV Index (0 - 11+) 3

Humidity 26 %

Today

Day 99°

Night 72°

Precipitation 0 %

Wind 8 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

22 minutes ago

Last updated on August 09, 2026 at 4:14 PM

Weather Forecast History

Last Year's Weather on This Day (August 9, 2025)

Day

93°

Night

66°

Wind

5 mph

Precipitation

0 %

Air Quality in Fontana

NOW

37 AQI

Good air quality Dominant pollutant: O₃

Pollutant Concentrations:

PM_2.5 7.63 µg/m³

PM₁₀ 19.94 µg/m³

O₃ 0.040 ppm

NO₂ 0.1 ppb

SO₂ 0.2 ppb

CO 0.06 ppm

NH₃ 0 µg/m³

NO 0.04 µg/m³

PM_2.5 – 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)

PM_2.5 – 7.63 µg/m³

PM₁₀ – 19.94 µg/m³

O₃ – 78.16 µg/m³

NO₂ – 0.25 µg/m³

SO₂ – 0.51 µg/m³

CO – 73.7 µg/m³

NH₃ – 0 µg/m³

NO – 0.04 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Fontana

Moderate Expected Likely

Heat Advisory

Heat Advisory issued August 9 at 12:53PM PDT until August 9 at 8:00PM PDT by NWS San Diego CA

Aug 9, 12:53 PM → Aug 9, 8:00 PM

WHAT: Temperatures up to 103.

WHERE: San Bernardino and Riverside County Valleys-The Inland
Empire.

WHEN: Until 8 PM PDT this evening.

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.

Updated: Aug 9, 4:14 PM Source: NWS Alert