Heat Persists in the South Central U.S. and California; Heavy Rain in the Ohio Valley

Sweltering heat remains across the South-Central Plains and Lower/Middle Mississippi Valley, as well as in the Southwest and California this week with limited nighttime relief. Heavy rainfall will lead to localized areas of flash flooding in parts of the Ohio Valley/Central Appalachians. Dry and breezy conditions will enhance fire weather concerns across the northern Rockies and High Plains. Read More >

Hazardous Weather Conditions

Current conditions at

Mount Sterling, Mount Sterling Municipal Airport (KI63)

Lat: 39.99°NLon: 90.8°WElev: 732ft.

Fair

69°F

21°C

Humidity 98%
Wind Speed Calm
Barometer 30.06 in
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Last update 9 Sep 8:35 pm CDT
Extended Forecast for

Frederick IL

  • Tonight

    Tonight: A slight chance of showers, then a chance of showers and thunderstorms after 1am.  Mostly cloudy, with a low around 68. Light and variable wind.  Chance of precipitation is 50%.

    Low: 68 °F

    Mostly Cloudy
    then Chance
    Showers

  • Thursday

    Thursday: Showers and thunderstorms likely, mainly before 2pm.  Cloudy, with a high near 81. Light and variable wind.  Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 81 °F

    Showers
    Likely then
    Chance
    Showers

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 60. Calm wind.

    Low: 60 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 83. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 83 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 64. Calm wind.

    Low: 64 °F

    Mostly Clear

  • Saturday

    Saturday: A 40 percent chance of showers before 1pm.  Mostly sunny, with a high near 86. Calm wind becoming south southwest around 5 mph.

    High: 86 °F

    Chance
    Showers

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 65. Calm wind.

    Low: 65 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 86.

    High: 86 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 68.

    Low: 68 °F

    Partly Cloudy

Detailed Forecast

Tonight
A slight chance of showers, then a chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 68. Light and variable wind. Chance of precipitation is 50%.
Thursday
Showers and thunderstorms likely, mainly before 2pm. Cloudy, with a high near 81. Light and variable wind. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday Night
Partly cloudy, with a low around 60. Calm wind.
Friday
Sunny, with a high near 83. Calm wind becoming southeast around 5 mph in the afternoon.
Friday Night
Mostly clear, with a low around 64. Calm wind.
Saturday
A 40 percent chance of showers before 1pm. Mostly sunny, with a high near 86. Calm wind becoming south southwest around 5 mph.
Saturday Night
Partly cloudy, with a low around 65. Calm wind.
Sunday
Partly sunny, with a high near 86.
Sunday Night
Partly cloudy, with a low around 68.
Monday
Mostly sunny, with a high near 92.
Monday Night
A chance of showers and thunderstorms. Mostly clear, with a low around 68.
Tuesday
A chance of showers. Partly sunny, with a high near 84.
Tuesday Night
A chance of showers. Partly cloudy, with a low around 63.
Wednesday
A chance of showers. Mostly sunny, with a high near 84.
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ABOUT THIS FORECAST

 
Point Forecast:
Frederick IL
 40.06°N 90.43°W (Elev. 440 ft)
6:11 pm CDT Sep 9, 2026
8pm CDT Sep 9, 2026-6pm CDT Sep 16, 2026
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database