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

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Mostly Cloudy

33°F

1°C

Humidity 45%
Wind Speed S 7 mph
Barometer 30.12 in (1020.4 mb)
Dewpoint 14°F (-10°C)
Visibility 10.00 mi
Wind Chill27°F (-3°C)
Last update 15 Dec 8:53 pm CST
Extended Forecast for

Waterloo IL

  • Tonight

    Tonight: Mostly cloudy, with a low around 28. South wind 5 to 7 mph.

    Low: 28 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 45. South wind 7 to 11 mph.

    High: 45 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 34. Southwest wind 5 to 9 mph.

    Low: 34 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 53. Calm wind becoming southeast 5 to 7 mph in the afternoon.

    High: 53 °F

    Sunny

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers after midnight. Mostly cloudy, with a temperature falling to near 41 by 8pm, then rising to around 51 during the remainder of the night. South wind 7 to 14 mph, with gusts as high as 23 mph.

    Low: 41 °F⇑

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm before noon, then a chance of showers between noon and 3pm. Partly sunny, with a temperature rising to near 55 by 9am, then falling to around 44 during the remainder of the day. Chance of precipitation is 70%.

    High: 55 °F⇓

    Showers
    Likely then
    Chance
    Showers

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 20.

    Low: 20 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 39.

    High: 39 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 32.

    Low: 32 °F

    Partly Cloudy

Detailed Forecast

Tonight
Mostly cloudy, with a low around 28. South wind 5 to 7 mph.
Tuesday
Mostly sunny, with a high near 45. South wind 7 to 11 mph.
Tuesday Night
Mostly cloudy, with a low around 34. Southwest wind 5 to 9 mph.
Wednesday
Sunny, with a high near 53. Calm wind becoming southeast 5 to 7 mph in the afternoon.
Wednesday Night
A 20 percent chance of showers after midnight. Mostly cloudy, with a temperature falling to near 41 by 8pm, then rising to around 51 during the remainder of the night. South wind 7 to 14 mph, with gusts as high as 23 mph.
Thursday
Showers likely and possibly a thunderstorm before noon, then a chance of showers between noon and 3pm. Partly sunny, with a temperature rising to near 55 by 9am, then falling to around 44 during the remainder of the day. Chance of precipitation is 70%.
Thursday Night
Partly cloudy, with a low around 20.
Friday
Sunny, with a high near 39.
Friday Night
Partly cloudy, with a low around 32.
Saturday
Mostly sunny, with a high near 56.
Saturday Night
Mostly cloudy, with a low around 33.
Sunday
Mostly sunny, with a high near 48.
Sunday Night
Mostly cloudy, with a low around 35.
Monday
Partly sunny, with a high near 56.
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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:
8:56 pm CST Dec 15, 2025
Forecast Valid:
10pm CST Dec 15, 2025-6pm CST Dec 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