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

Extreme Heat Continues; Severe Thunderstorms into Upper Midwest; Strong Bering Sea Storm

Wildfires and poor air quality continue for the Pacific Northwest, Rockies and extended into the Plains. Severe thunderstorms possible for the northern Plains and upper Midwest on Monday along a frontal boundary. Another boundary will focus showers and thunderstorms for the eastern seaboard with localized heavy rainfall possible. For Alaska, a strong Bering Sea storm will bring winds and rainfall. Read More >

Current conditions at

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

Lat: 38.93°NLon: 90.43°WElev: 436ft.

Fair

67°F

19°C

Humidity 91%
Wind Speed Calm
Barometer 29.91 in (1012.5 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Last update 3 Aug 1:54 am CDT
Extended Forecast for

Portage Des Sioux MO

  • Overnight

    Overnight: Clear, with a low around 65. Calm wind.

    Low: 65 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 86. Light north wind.

    High: 86 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 65. Light east wind.

    Low: 65 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 89. Calm wind becoming south around 5 mph.

    High: 89 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 68. East wind 3 to 5 mph.

    Low: 68 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 91.

    High: 91 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely after 1am. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.

    Low: 71 °F

    Partly Cloudy
    then T-storms
    Likely

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm before 1pm, then a slight chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 87. Chance of precipitation is 60%.

    High: 87 °F

    Showers
    Likely

  • Thursday Night

    Thursday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69.

    Low: 69 °F

    Chance
    T-storms

Detailed Forecast

Overnight
Clear, with a low around 65. Calm wind.
Monday
Sunny, with a high near 86. Light north wind.
Monday Night
Mostly clear, with a low around 65. Light east wind.
Tuesday
Sunny, with a high near 89. Calm wind becoming south around 5 mph.
Tuesday Night
Mostly clear, with a low around 68. East wind 3 to 5 mph.
Wednesday
Sunny, with a high near 91.
Wednesday Night
Showers and thunderstorms likely after 1am. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.
Thursday
Showers likely and possibly a thunderstorm before 1pm, then a slight chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 87. Chance of precipitation is 60%.
Thursday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69.
Friday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 87.
Friday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 69.
Saturday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
Saturday Night
Partly cloudy, with a low around 71.
Sunday
Mostly sunny, with a high near 92.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Portage Des Sioux MO
 38.93°N 90.36°W (Elev. 407 ft)
Last Update:
2:21 am CDT Aug 3, 2026
Forecast Valid:
2am CDT Aug 3, 2026-6pm CDT Aug 9, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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