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

Mattoon / Charleston, Coles County Memorial Airport (KMTO)

Lat: 39.48°NLon: 88.28°WElev: 722ft.

Fair

68°F

20°C

Humidity 78%
Wind Speed Calm
Barometer 30.02 in (1015.9 mb)
Dewpoint 61°F (16°C)
Visibility 10.00 mi
Last update 19 Jun 8:53 pm CDT
Extended Forecast for

Sullivan IL

  • Tonight

    Tonight: A 20 percent chance of showers after 3am. Mostly cloudy, with a low around 61. Southwest wind 3 to 5 mph.

    Low: 61 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Saturday

    Saturday: Mostly sunny, with a high near 81. Northwest wind 5 to 7 mph.

    High: 81 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. Northwest wind around 5 mph becoming calm.

    Low: 61 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Sunday

    Sunday: A chance of showers before 7am, then showers likely and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 78. East southeast wind 7 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

    High: 78 °F

    Showers
    Likely then
    T-storms

  • Sunday Night

    Sunday Night: Showers and thunderstorms, mainly before 1am. Low around 62. South southwest wind 11 to 15 mph becoming north northwest after midnight. Winds could gust as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.

    Low: 62 °F

    T-storms

  • Monday

    Monday: Partly sunny, with a high near 74. North wind 11 to 13 mph, with gusts as high as 20 mph.

    High: 74 °F

    Partly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 55. North northeast wind 6 to 10 mph, with gusts as high as 16 mph.

    Low: 55 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 76.

    High: 76 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 58.

    Low: 58 °F

    Partly Cloudy

Detailed Forecast

Tonight
A 20 percent chance of showers after 3am. Mostly cloudy, with a low around 61. Southwest wind 3 to 5 mph.
Saturday
Mostly sunny, with a high near 81. Northwest wind 5 to 7 mph.
Saturday Night
A 20 percent chance of showers after 4am. Partly cloudy, with a low around 61. Northwest wind around 5 mph becoming calm.
Sunday
A chance of showers before 7am, then showers likely and possibly a thunderstorm between 7am and 1pm, then showers and thunderstorms after 1pm. High near 78. East southeast wind 7 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Sunday Night
Showers and thunderstorms, mainly before 1am. Low around 62. South southwest wind 11 to 15 mph becoming north northwest after midnight. Winds could gust as high as 22 mph. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Monday
Partly sunny, with a high near 74. North wind 11 to 13 mph, with gusts as high as 20 mph.
Monday Night
Partly cloudy, with a low around 55. North northeast wind 6 to 10 mph, with gusts as high as 16 mph.
Tuesday
Mostly sunny, with a high near 76.
Tuesday Night
Partly cloudy, with a low around 58.
Wednesday
Sunny, with a high near 77.
Wednesday Night
Mostly clear, with a low around 58.
Thursday
Mostly sunny, with a high near 77.
Thursday Night
Partly cloudy, with a low around 58.
Friday
Mostly sunny, with a high near 78.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Sullivan IL
 39.61°N 88.61°W (Elev. 669 ft)
Last Update:
7:51 pm CDT Jun 19, 2026
Forecast Valid:
9pm CDT Jun 19, 2026-6pm CDT Jun 26, 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