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

Dangerous Heat and Possible Flooding

Dangerous heat will persist across the Southwest U.S. through Saturday with daytime highs of 110-115°F. Extreme Heat Warnings remain in effect. Dangerous heat will build across the southern Plains again beginning this weekend. Heavy to excessive rain over the Carolinas Friday may lead to isolated areas of flash flooding. Read More >

Hazardous Weather Conditions

Current conditions at

Chamberlain, Chamberlain Municipal Airport (K9V9)

Lat: 43.77°NLon: 99.32°WElev: 1693ft.

Fair

87°F

31°C

Humidity 51%
Wind Speed SE 15 G 23 mph
Barometer 29.85 in
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Heat Index90°F (32°C)
Last update 28 Aug 6:15 pm CDT
Extended Forecast for

Gann Valley SD

  • Tonight

    Tonight: Showers and thunderstorms likely, mainly before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 67. Southeast wind 10 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 67 °F

    Showers
    Likely then
    Chance
    T-storms

  • Saturday

    Saturday: Mostly sunny and hot, with a high near 90. Southeast wind around 6 mph becoming northwest in the morning.

    High: 90 °F

    Hot

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms between 11pm and midnight. Mostly cloudy, then gradually becoming mostly clear, with a low around 67. East wind 6 to 8 mph. Chance of precipitation is 30%.

    Low: 67 °F

    Chance
    Showers then
    Mostly Cloudy

  • Sunday

    Sunday: Cloudy through mid morning, then gradual clearing and hot, with a high near 91. East wind 6 to 10 mph becoming southwest in the afternoon. Winds could gust as high as 20 mph.

    High: 91 °F

    Hot

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 66. West southwest wind around 8 mph becoming north northwest after midnight.

    Low: 66 °F

    Mostly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 86. North northwest wind 9 to 11 mph becoming east in the afternoon. Winds could gust as high as 20 mph.

    High: 86 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 64. East wind 5 to 7 mph.

    Low: 64 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 85. Light east wind becoming southeast 5 to 9 mph in the morning. Chance of precipitation is 30%.

    High: 85 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 63. East wind 6 to 9 mph. Chance of precipitation is 30%.

    Low: 63 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Showers and thunderstorms likely, mainly before 2am. Cloudy, then gradually becoming partly cloudy, with a low around 67. Southeast wind 10 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
Mostly sunny and hot, with a high near 90. Southeast wind around 6 mph becoming northwest in the morning.
Saturday Night
A chance of showers and thunderstorms between 11pm and midnight. Mostly cloudy, then gradually becoming mostly clear, with a low around 67. East wind 6 to 8 mph. Chance of precipitation is 30%.
Sunday
Cloudy through mid morning, then gradual clearing and hot, with a high near 91. East wind 6 to 10 mph becoming southwest in the afternoon. Winds could gust as high as 20 mph.
Sunday Night
Mostly cloudy, with a low around 66. West southwest wind around 8 mph becoming north northwest after midnight.
Monday
Mostly sunny, with a high near 86. North northwest wind 9 to 11 mph becoming east in the afternoon. Winds could gust as high as 20 mph.
Monday Night
Partly cloudy, with a low around 64. East wind 5 to 7 mph.
Tuesday
A chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 85. Light east wind becoming southeast 5 to 9 mph in the morning. Chance of precipitation is 30%.
Tuesday Night
A chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 63. East wind 6 to 9 mph. Chance of precipitation is 30%.
Wednesday
Mostly sunny, with a high near 89.
Wednesday Night
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 66. Chance of precipitation is 20%.
Thursday
Partly sunny, with a high near 89.
Thursday Night
A slight chance of showers and thunderstorms. Mostly clear, with a low around 65. Chance of precipitation is 20%.
Friday
Mostly sunny, with a high near 88.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Gann Valley SD
 44.04°N 98.98°W (Elev. 1709 ft)
Last Update:
6:06 pm CDT Aug 28, 2026
Forecast Valid:
6pm CDT Aug 28, 2026-6pm CDT Sep 4, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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