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

62°F

17°C

Humidity 80%
Wind Speed S 8 mph
Barometer 29.94 in (1013.4 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 17 Apr 1:53 am CDT
Extended Forecast for

Sullivan IL

  • Overnight

    Overnight: Mostly clear, with a low around 56. South wind around 5 mph.

    Low: 56 °F

    Mostly Clear

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 82. South wind 7 to 12 mph increasing to 13 to 18 mph in the afternoon. Winds could gust as high as 29 mph.

    High: 82 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Friday Night

    Friday Night: Showers and thunderstorms likely, then showers and possibly a thunderstorm after midnight. Some of the storms could produce heavy rainfall. Low around 48. South wind around 15 mph becoming west after midnight. Winds could gust as high as 25 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 48 °F

    Showers
    Likely then
    Heavy Rain

  • Saturday

    Saturday: A 50 percent chance of showers before 1pm. Cloudy through mid morning, then gradual clearing, with a high near 57. Northwest wind 15 to 18 mph, with gusts as high as 28 mph.

    High: 57 °F

    Chance
    Showers

  • Saturday Night

    Saturday Night: Patchy frost after 3am. Otherwise, mostly clear, with a low around 36. Northwest wind 7 to 14 mph, with gusts as high as 22 mph.

    Low: 36 °F

    Mostly Clear
    then Patchy
    Frost

  • Sunday

    Sunday: Patchy frost before 8am. Otherwise, sunny, with a high near 59. West northwest wind 7 to 16 mph, with gusts as high as 26 mph.

    High: 59 °F

    Patchy Frost
    then Sunny

  • Sunday Night

    Sunday Night: Patchy frost after 3am. Otherwise, mostly clear, with a low around 36. Northwest wind 6 to 9 mph becoming east after midnight. Winds could gust as high as 15 mph.

    Low: 36 °F

    Mostly Clear
    then Patchy
    Frost

  • Monday

    Monday: Patchy frost before 8am. Otherwise, sunny, with a high near 63.

    High: 63 °F

    Patchy Frost
    then Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 48.

    Low: 48 °F

    Mostly Clear

Detailed Forecast

Overnight
Mostly clear, with a low around 56. South wind around 5 mph.
Friday
A 20 percent chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 82. South wind 7 to 12 mph increasing to 13 to 18 mph in the afternoon. Winds could gust as high as 29 mph.
Friday Night
Showers and thunderstorms likely, then showers and possibly a thunderstorm after midnight. Some of the storms could produce heavy rainfall. Low around 48. South wind around 15 mph becoming west after midnight. Winds could gust as high as 25 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Saturday
A 50 percent chance of showers before 1pm. Cloudy through mid morning, then gradual clearing, with a high near 57. Northwest wind 15 to 18 mph, with gusts as high as 28 mph.
Saturday Night
Patchy frost after 3am. Otherwise, mostly clear, with a low around 36. Northwest wind 7 to 14 mph, with gusts as high as 22 mph.
Sunday
Patchy frost before 8am. Otherwise, sunny, with a high near 59. West northwest wind 7 to 16 mph, with gusts as high as 26 mph.
Sunday Night
Patchy frost after 3am. Otherwise, mostly clear, with a low around 36. Northwest wind 6 to 9 mph becoming east after midnight. Winds could gust as high as 15 mph.
Monday
Patchy frost before 8am. Otherwise, sunny, with a high near 63.
Monday Night
Mostly clear, with a low around 48.
Tuesday
Mostly sunny, with a high near 76.
Tuesday Night
Mostly clear, with a low around 54.
Wednesday
Sunny, with a high near 77.
Wednesday Night
Mostly clear, with a low around 56.
Thursday
Mostly sunny, with a high near 80.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Sullivan IL
 39.59°N 88.61°W (Elev. 669 ft)
Last Update:
1:26 am CDT Apr 17, 2026
Forecast Valid:
2am CDT Apr 17, 2026-6pm CDT Apr 23, 2026
 
Forecast Discussion
 
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Additional Resources

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High Temperature

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Chance of Precipitation