National Weather Service Forecast for: Yankton SD
Issued by: National Weather Service Sioux Falls, SD
Updated: 2:39 am CDT Aug 20, 2026
 
Overnight

Overnight: Patchy fog after 5am. Otherwise, mostly clear, with a low around 59. South southwest wind around 5 mph.
Patchy Fog

 Thursday

Thursday: A 20 percent chance of showers and thunderstorms after 4pm. Sunny, with a high near 86. South wind 5 to 15 mph, with gusts as high as 20 mph.
Sunny then
Slight Chance
T-storms
 Thursday
Night
Thursday Night: A 20 percent chance of showers and thunderstorms before 9pm. Mostly clear, with a low around 63. West southwest wind 5 to 10 mph.
Slight Chance
T-storms then
Mostly Clear
 Friday

Friday: Sunny, with a high near 86. Calm wind becoming east around 5 mph in the afternoon.
Sunny

 Friday
Night
Friday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 62. East wind around 5 mph becoming calm in the evening.
Slight Chance
T-storms

 Saturday

Saturday: Sunny, with a high near 83. Northeast wind around 5 mph.
Sunny

 Saturday
Night
Saturday Night: Partly cloudy, with a low around 59.
Partly Cloudy

 Sunday

Sunday: A 30 percent chance of showers. Partly sunny, with a high near 79.
Chance
Showers

 Sunday
Night
Sunday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.
Chance
T-storms then
Showers
Likely
Lo 59 °F Hi 86 °F Lo 63 °F Hi 86 °F Lo 62 °F Hi 83 °F Lo 59 °F Hi 79 °F Lo 62 °F

Hazardous Weather Outlook
 

Overnight
 
 Patchy fog after 5am. Otherwise, mostly clear, with a low around 59. South southwest wind around 5 mph.
Thursday
 
 A 20 percent chance of showers and thunderstorms after 4pm. Sunny, with a high near 86. South wind 5 to 15 mph, with gusts as high as 20 mph.
Thursday Night
 
 A 20 percent chance of showers and thunderstorms before 9pm. Mostly clear, with a low around 63. West southwest wind 5 to 10 mph.
Friday
 
 Sunny, with a high near 86. Calm wind becoming east around 5 mph in the afternoon.
Friday Night
 
 A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 62. East wind around 5 mph becoming calm in the evening.
Saturday
 
 Sunny, with a high near 83. Northeast wind around 5 mph.
Saturday Night
 
 Partly cloudy, with a low around 59.
Sunday
 
 A 30 percent chance of showers. Partly sunny, with a high near 79.
Sunday Night
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.
Monday
 
 Mostly sunny, with a high near 83.
Monday Night
 
 Partly cloudy, with a low around 64.
Tuesday
 
 Mostly sunny, with a high near 84.
Tuesday Night
 
 A 30 percent chance of showers. Partly cloudy, with a low around 63.
Wednesday
 
 Mostly sunny, with a high near 83.

 

Forecast from NOAA-NWS for Yankton SD.