Dangerous Heat in the Southwest; Severe Thunderstorms and Heavy Rain in the Northeast and Mid-Atlantic

Dangerous heat will persist across the Southwest U.S. through Friday with daytime highs of 110-115°F. Heat across the southern Plains will briefly ease to near-normal by late week. Strong to severe thunderstorms may produce damaging wind, hail, a tornado or two, heavy rain and flash flooding across parts of the Mid-Atlantic and Northeast. Heavy rainfall threat continues across the Gulf Coast. Read More >

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

85°F

29°C

Humidity 43%
Wind Speed NW 12 mph
Barometer 30.01 in (1015.7 mb)
Dewpoint 60°F (16°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 27 Aug 4:53 pm CDT
Extended Forecast for

Collinsville IL

  • Tonight

    Tonight: Mostly clear, with a low around 64. North wind 5 to 8 mph becoming calm  in the evening.

    Low: 64 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 87. Calm wind becoming north around 5 mph in the afternoon.

    High: 87 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 64. Light and variable wind.

    Low: 64 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 89. Calm wind becoming south 5 to 7 mph in the morning.

    High: 89 °F

    Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 69. South wind around 7 mph.

    Low: 69 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 95.

    High: 95 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 74.

    Low: 74 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 97.

    High: 97 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 77.

    Low: 77 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 64. North wind 5 to 8 mph becoming calm in the evening.
Friday
Sunny, with a high near 87. Calm wind becoming north around 5 mph in the afternoon.
Friday Night
Mostly clear, with a low around 64. Light and variable wind.
Saturday
Sunny, with a high near 89. Calm wind becoming south 5 to 7 mph in the morning.
Saturday Night
Partly cloudy, with a low around 69. South wind around 7 mph.
Sunday
Sunny, with a high near 95.
Sunday Night
Mostly clear, with a low around 74.
Monday
Sunny and hot, with a high near 97.
Monday Night
Mostly clear, with a low around 77.
Tuesday
Sunny and hot, with a high near 97.
Tuesday Night
Mostly clear, with a low around 78.
Wednesday
Sunny and hot, with a high near 98.
Wednesday Night
Mostly clear, with a low around 79.
Thursday
Sunny and hot, with a high near 97.
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ABOUT THIS FORECAST

 
Point Forecast:
Collinsville IL
 38.68°N 90°W (Elev. 499 ft)
1:26 pm CDT Aug 27, 2026
5pm CDT Aug 27, 2026-6pm CDT Sep 3, 2026
 
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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