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Watching Hurricane Erin; Heavy Rainfall Threat for Upper Midwest; Heatrisk for Mississippi Valley

Hurricane Erin continues to track westward with its outer bands bringing heavy rainfall and gusty winds for Puerto Rico and US Virgin Islands. Life-threatening surf and rip currents are occurring and will spread across the Atlantic coasts this week. Meanwhile, heavy rainfall and possible flooding are in the forecast for upper Midwest through Monday. Heatrisk continues for the Mississippi Valley. Read More >

Hazardous Weather Conditions

Current conditions at

Sisseton, Sisseton Municipal Airport (K8D3)

Lat: 45.67°NLon: 96.99°WElev: 1161ft.

70°F

21°C

Humidity 100%
Wind Speed SE 5 mph
Barometer 29.88 in (1010.4 mb)
Dewpoint 70°F (21°C)
Visibility NA
Last update 18 Aug 3:56 am CDT
Extended Forecast for

6 Miles E Grenville SD

Dense Fog Advisory until August 18, 09:00am
Click here for hazard details and duration
Dense Fog Advisory
  •  
    Dense Fog Advisory until August 18, 09:00am

    NOW until 9:00am Mon

    Dense Fog Advisory

  • Overnight

    Low: 69 °F

    Areas Dense
    Fog

  • Monday

    Monday: Widespread dense fog, mainly before 8am. Otherwise, mostly sunny, with a high near 79. Light west wind becoming northwest 5 to 9 mph in the morning.

    High: 79 °F

    Dense Fog
    then Sunny

  • Monday Night

    Monday Night: Patchy fog after 5am. Otherwise, partly cloudy, with a low around 64. North wind around 6 mph becoming light and variable in the evening.

    Low: 64 °F

    Partly Cloudy
    then Patchy
    Fog

  • Tuesday

    Tuesday: Patchy fog before 9am. Otherwise, mostly sunny, with a high near 81. East wind 3 to 6 mph.

    High: 81 °F

    Patchy Fog
    then Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 64. East northeast wind around 6 mph becoming south southeast after midnight.

    Low: 64 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 80. South southeast wind 6 to 10 mph.

    High: 80 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 64. Southeast wind around 11 mph, with gusts as high as 22 mph.

    Low: 64 °F

    Mostly Clear

  • Thursday

    Thursday: A slight chance of showers after 1pm. Sunny, with a high near 82. South wind 11 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

    High: 82 °F

    Sunny then
    Slight Chance
    Showers

Detailed Forecast

Overnight
Areas of dense fog. Otherwise, partly cloudy, with a steady temperature around 69. Light southeast wind.
Monday
Widespread dense fog, mainly before 8am. Otherwise, mostly sunny, with a high near 79. Light west wind becoming northwest 5 to 9 mph in the morning.
Monday Night
Patchy fog after 5am. Otherwise, partly cloudy, with a low around 64. North wind around 6 mph becoming light and variable in the evening.
Tuesday
Patchy fog before 9am. Otherwise, mostly sunny, with a high near 81. East wind 3 to 6 mph.
Tuesday Night
Mostly clear, with a low around 64. East northeast wind around 6 mph becoming south southeast after midnight.
Wednesday
Sunny, with a high near 80. South southeast wind 6 to 10 mph.
Wednesday Night
Mostly clear, with a low around 64. Southeast wind around 11 mph, with gusts as high as 22 mph.
Thursday
A slight chance of showers after 1pm. Sunny, with a high near 82. South wind 11 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 60. South wind 7 to 9 mph becoming north in the evening. Chance of precipitation is 50%.
Friday
A slight chance of showers before 1pm. Sunny, with a high near 73. Chance of precipitation is 20%.
Friday Night
Mostly clear, with a low around 54.
Saturday
Sunny, with a high near 66.
Saturday Night
Mostly clear, with a low around 49.
Sunday
Sunny, with a high near 65.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
6 Miles E Grenville SD
 45.48°N 97.25°W (Elev. 1900 ft)
Last Update:
4:46 am CDT Aug 18, 2025
Forecast Valid:
4am CDT Aug 18, 2025-6pm CDT Aug 24, 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