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

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Hazardous Weather Conditions

Current conditions at

Lewis University Airport (KLOT)

Lat: 41.6°NLon: 88.1°WElev: 669ft.

Rain

66°F

19°C

Humidity 100%
Wind Speed NE 16 mph
Barometer 29.99 in
Dewpoint 66°F (19°C)
Visibility 3.00 mi
Last update 19 Sep 5:45 am CDT
Extended Forecast for

Frankfort IL

Flood Watch until September 19, 01:00pm
Click here for hazard details and duration
Flood Watch
  •  
    Flood Watch until September 19, 01:00pm

    NOW until 1:00pm Sat

    Flood Watch

  • Today

    High: 78 °F

    Heavy Rain
    then T-storms
    Likely

  • Tonight

    Tonight: Showers and thunderstorms likely, then showers and possibly a thunderstorm after midnight. Low around 64. Southeast wind around 5 mph becoming north northwest after midnight. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.

    Low: 64 °F

    T-storms

  • Sunday

    Sunday: Showers likely and possibly a thunderstorm. Cloudy, with a high near 70. North northeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

    High: 70 °F

    Showers
    Likely

  • Sunday Night

    Sunday Night: A 40 percent chance of showers. Mostly cloudy, with a low around 56. East northeast wind around 15 mph, with gusts as high as 25 mph.

    Low: 56 °F

    Chance
    Showers

  • Monday

    Monday: A 40 percent chance of showers. Mostly cloudy, with a high near 65. East northeast wind around 15 mph, with gusts as high as 25 mph.

    High: 65 °F

    Chance
    Showers

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 52.

    Low: 52 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 63.

    High: 63 °F

    Slight Chance
    Showers

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 52.

    Low: 52 °F

    Mostly Cloudy

Detailed Forecast

Today
Showers and possibly a thunderstorm before noon, then showers and thunderstorms likely, mainly between noon and 1pm. Some of the storms could produce heavy rainfall. High near 78. East wind 5 to 10 mph becoming south in the afternoon. Winds could gust as high as 15 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
Tonight
Showers and thunderstorms likely, then showers and possibly a thunderstorm after midnight. Low around 64. Southeast wind around 5 mph becoming north northwest after midnight. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Sunday
Showers likely and possibly a thunderstorm. Cloudy, with a high near 70. North northeast wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.
Sunday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 56. East northeast wind around 15 mph, with gusts as high as 25 mph.
Monday
A 40 percent chance of showers. Mostly cloudy, with a high near 65. East northeast wind around 15 mph, with gusts as high as 25 mph.
Monday Night
Mostly cloudy, with a low around 52.
Tuesday
A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 63.
Tuesday Night
Mostly cloudy, with a low around 52.
Wednesday
Partly sunny, with a high near 65.
Wednesday Night
Mostly cloudy, with a low around 53.
Thursday
Partly sunny, with a high near 67.
Thursday Night
Mostly cloudy, with a low around 53.
Friday
Mostly sunny, with a high near 71.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Frankfort IL
 41.49°N 87.85°W
Last Update:
3:46 am CDT Sep 19, 2026
Forecast Valid:
6am CDT Sep 19, 2026-6pm CDT Sep 25, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation