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 >

Current conditions at

Custer, Custer County Airport (KCUT)

Lat: 43.73°NLon: 103.62°WElev: 5600ft.

Fair

64°F

18°C

Humidity 60%
Wind Speed NW 3 mph
Barometer 30.07 in (1010.4 mb)
Dewpoint 50°F (10°C)
Visibility 10.00 mi
Last update 28 Aug 11:53 pm MDT
Extended Forecast for

Keystone SD

  • Overnight

    Overnight: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 65. Light west wind.

    Low: 65 °F

    Slight Chance
    T-storms

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 89. Calm wind becoming west 5 to 7 mph in the afternoon. Winds could gust as high as 25 mph.

    High: 89 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 20 percent chance of showers and thunderstorms before 9pm. Mostly cloudy, with a low around 64. West wind around 7 mph, with gusts as high as 24 mph.

    Low: 64 °F

    Slight Chance
    T-storms then
    Mostly Cloudy

  • Sunday

    Sunday: A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 86. Southwest wind 5 to 10 mph, with gusts as high as 32 mph.

    High: 86 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 57. West wind 5 to 8 mph becoming calm after midnight. Winds could gust as high as 29 mph.

    Low: 57 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 82. Calm wind becoming south 5 to 7 mph in the morning. Winds could gust as high as 23 mph.

    High: 82 °F

    Sunny

  • Monday Night

    Monday Night: A 20 percent chance of showers after midnight. Partly cloudy, with a low around 60.

    Low: 60 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Tuesday

    Tuesday: A slight chance of showers and thunderstorms after noon. Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 62.

    Low: 62 °F

    Partly Cloudy

Detailed Forecast

Overnight
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 65. Light west wind.
Saturday
A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 89. Calm wind becoming west 5 to 7 mph in the afternoon. Winds could gust as high as 25 mph.
Saturday Night
A 20 percent chance of showers and thunderstorms before 9pm. Mostly cloudy, with a low around 64. West wind around 7 mph, with gusts as high as 24 mph.
Sunday
A 20 percent chance of showers and thunderstorms after noon. Mostly sunny, with a high near 86. Southwest wind 5 to 10 mph, with gusts as high as 32 mph.
Sunday Night
Partly cloudy, with a low around 57. West wind 5 to 8 mph becoming calm after midnight. Winds could gust as high as 29 mph.
Monday
Sunny, with a high near 82. Calm wind becoming south 5 to 7 mph in the morning. Winds could gust as high as 23 mph.
Monday Night
A 20 percent chance of showers after midnight. Partly cloudy, with a low around 60.
Tuesday
A slight chance of showers and thunderstorms after noon. Mostly sunny, with a high near 84.
Tuesday Night
Partly cloudy, with a low around 62.
Wednesday
Sunny, with a high near 88.
Wednesday Night
Partly cloudy, with a low around 64.
Thursday
Mostly sunny, with a high near 85.
Thursday Night
Partly cloudy, with a low around 62.
Friday
Sunny, with a high near 84.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Keystone SD
 43.89°N 103.43°W (Elev. 4541 ft)
Last Update:
10:46 pm MDT Aug 28, 2026
Forecast Valid:
12am MDT Aug 29, 2026-6pm MDT Sep 4, 2026
 
Forecast Discussion
 
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Additional Resources

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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