National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Fontana-Arrow Highway (CQ057)

Lat: 34.10056°NLon: 117.49222°WElev: 1191.0ft.

NA

103°F

39°C

Humidity 20%
Wind Speed WSW 8 MPH
Barometer NA
Dewpoint 56°F (13°C)
Visibility NA
Heat Index101°F (38°C)
Last update 26 Aug 06:00 PM PDT
Extended Forecast for

Rancho Cucamonga CA

Extreme Heat Warning August 26, 07:09pm until August 28, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning August 26, 07:09pm until August 28, 08:00pm

    NOW until 8:00pm Fri

    Extreme Heat Warning

  • Tonight

    Low: 75 °F

    Increasing
    Clouds

  • Thursday

    Thursday: Mostly cloudy, with a high near 103. Light and variable wind becoming west 5 to 10 mph in the afternoon.

    High: 103 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 74. Southwest wind 5 to 10 mph becoming light west in the evening.

    Low: 74 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 101. Light southwest wind increasing to 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.

    High: 101 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 73. Southwest wind 5 to 10 mph becoming light in the evening.

    Low: 73 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 99.

    High: 99 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 69.

    Low: 69 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 93.

    High: 93 °F

    Sunny

Detailed Forecast

Tonight
Increasing clouds, with a low around 75. Southwest wind 5 to 10 mph becoming light and variable in the evening.
Thursday
Mostly cloudy, with a high near 103. Light and variable wind becoming west 5 to 10 mph in the afternoon.
Thursday Night
Mostly cloudy, with a low around 74. Southwest wind 5 to 10 mph becoming light west in the evening.
Friday
Mostly sunny, with a high near 101. Light southwest wind increasing to 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Friday Night
Mostly clear, with a low around 73. Southwest wind 5 to 10 mph becoming light in the evening.
Saturday
Sunny, with a high near 99.
Saturday Night
Clear, with a low around 69.
Sunday
Sunny, with a high near 93.
Sunday Night
Clear, with a low around 64.
Monday
Sunny, with a high near 89.
Monday Night
A slight chance of showers. Mostly clear, with a low around 63.
Tuesday
A slight chance of showers. Mostly sunny, with a high near 89.
Tuesday Night
A slight chance of showers. Partly cloudy, with a low around 66.
Wednesday
A slight chance of showers. Mostly sunny, with a high near 90.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Rancho Cucamonga CA
 34.13°N 117.57°W (Elev. 1362 ft)
Last Update:
11:36 am PDT Aug 26, 2026
Forecast Valid:
7pm PDT Aug 26, 2026-6pm PDT Sep 2, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation