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

Hazardous Weather Conditions

Current conditions at

St. Charles, St. Charles County Smartt Airport (KSET)

Lat: 38.93°NLon: 90.43°WElev: 436ft.

Overcast

68°F

20°C

Humidity 87%
Wind Speed Calm
Barometer 30.00 in (1015.4 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Last update 20 Jun 4:54 am CDT
Extended Forecast for

5 Miles WNW Grafton IL

Flood Watch June 21, 07:00am until June 22, 01:00am
Click here for hazard details and duration
Flood Watch

  • Overnight

    Overnight: A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Light west wind.

    Low: 67 °F

    Slight Chance
    T-storms

  • Saturday

    Saturday: Partly sunny, with a high near 83. Northwest wind 3 to 5 mph.

    High: 83 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 68. Northeast wind 5 to 8 mph becoming east after midnight.

    Low: 68 °F

    Mostly Cloudy

  • Sunday

    Sunday: Showers and thunderstorms. Some of the storms could produce heavy rainfall. High near 81. Southeast wind 9 to 13 mph becoming south in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 100%.

    High: 81 °F

    Heavy Rain

  • Sunday Night

    Sunday Night: Showers and thunderstorms, mainly before 1am. Low around 63. Southwest wind around 10 mph becoming north after midnight. Chance of precipitation is 80%.

    Low: 63 °F

    T-storms

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms before 1pm. Partly sunny, with a high near 76.

    High: 76 °F

    Slight Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 60.

    Low: 60 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 79.

    High: 79 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 62.

    Low: 62 °F

    Mostly Clear

Detailed Forecast

Overnight
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Light west wind.
Saturday
Partly sunny, with a high near 83. Northwest wind 3 to 5 mph.
Saturday Night
Mostly cloudy, with a low around 68. Northeast wind 5 to 8 mph becoming east after midnight.
Sunday
Showers and thunderstorms. Some of the storms could produce heavy rainfall. High near 81. Southeast wind 9 to 13 mph becoming south in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 100%.
Sunday Night
Showers and thunderstorms, mainly before 1am. Low around 63. Southwest wind around 10 mph becoming north after midnight. Chance of precipitation is 80%.
Monday
A 20 percent chance of showers and thunderstorms before 1pm. Partly sunny, with a high near 76.
Monday Night
Partly cloudy, with a low around 60.
Tuesday
Mostly sunny, with a high near 79.
Tuesday Night
Mostly clear, with a low around 62.
Wednesday
Mostly sunny, with a high near 81.
Wednesday Night
Partly cloudy, with a low around 62.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 80.
Thursday Night
A 20 percent chance of showers. Partly cloudy, with a low around 62.
Friday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 81.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
5 Miles WNW Grafton IL
 39°N 90.5°W (Elev. 801 ft)
Last Update:
2:56 am CDT Jun 20, 2026
Forecast Valid:
5am CDT Jun 20, 2026-6pm CDT Jun 26, 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