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

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Partly Cloudy

81°F

27°C

Humidity 77%
Wind Speed S 3 mph
Barometer 30.09 in (1018.5 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 15 Aug 11:53 pm CDT
Extended Forecast for

Waterloo IL

Heat Advisory August 16, 12:32am until August 18, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 16, 12:32am until August 18, 08:00pm

    NOW until 8:00pm Mon

    Heat Advisory

  • Overnight

    Low: 74 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 97. Heat index values as high as 106. South wind around 6 mph.

    High: 97 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 74. Southeast wind around 5 mph becoming calm in the evening.

    Low: 74 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny and hot, with a high near 98. Heat index values as high as 109. Light southeast wind.

    High: 98 °F

    Hot

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 75. Light southeast wind.

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 98.

    High: 98 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 75.

    Low: 75 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 97.

    High: 97 °F

    Sunny then
    Slight Chance
    T-storms

Detailed Forecast

Overnight
Mostly clear, with a low around 74. South wind 3 to 5 mph.
Saturday
Sunny and hot, with a high near 97. Heat index values as high as 106. South wind around 6 mph.
Saturday Night
Mostly clear, with a low around 74. Southeast wind around 5 mph becoming calm in the evening.
Sunday
Sunny and hot, with a high near 98. Heat index values as high as 109. Light southeast wind.
Sunday Night
Mostly clear, with a low around 75. Light southeast wind.
Monday
Sunny and hot, with a high near 98.
Monday Night
Mostly clear, with a low around 75.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 97.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 74.
Wednesday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 86.
Wednesday Night
Partly cloudy, with a low around 67.
Thursday
Sunny, with a high near 85.
Thursday Night
Mostly clear, with a low around 65.
Friday
Sunny, with a high near 87.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Waterloo IL
 38.33°N 90.16°W (Elev. 600 ft)
Last Update:
11:26 pm CDT Aug 15, 2025
Forecast Valid:
12am CDT Aug 16, 2025-6pm CDT Aug 22, 2025
 
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