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

Overnight: Patchy fog. Otherwise, mostly clear, with a low around 57. Calm wind.
Patchy Fog

 Thursday

Thursday: Patchy fog before 10am. Otherwise, sunny, with a high near 81. South southwest wind 5 to 10 mph.
Patchy Fog
then Sunny
 Thursday
Night
Thursday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 63. South southwest wind 5 to 10 mph.
Slight Chance
T-storms
 Friday

Friday: Sunny, with a high near 82. West southwest wind around 5 mph becoming north northwest in the afternoon.
Sunny

 Friday
Night
Friday Night: Mostly clear, with a low around 60. Calm wind becoming north northeast around 5 mph.
Mostly Clear

 Saturday

Saturday: Sunny, with a high near 79. North wind around 5 mph.
Sunny

 Saturday
Night
Saturday Night: Partly cloudy, with a low around 56.
Partly Cloudy

 Sunday

Sunday: Partly sunny, with a high near 76.
Partly Sunny

 Sunday
Night
Sunday Night: A 40 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 59.
Mostly Cloudy
then Chance
T-storms
Lo 57 °F Hi 81 °F Lo 63 °F Hi 82 °F Lo 60 °F Hi 79 °F Lo 56 °F Hi 76 °F Lo 59 °F

Hazardous Weather Outlook
 

Overnight
 
 Patchy fog. Otherwise, mostly clear, with a low around 57. Calm wind.
Thursday
 
 Patchy fog before 10am. Otherwise, sunny, with a high near 81. South southwest wind 5 to 10 mph.
Thursday Night
 
 A 20 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 63. South southwest wind 5 to 10 mph.
Friday
 
 Sunny, with a high near 82. West southwest wind around 5 mph becoming north northwest in the afternoon.
Friday Night
 
 Mostly clear, with a low around 60. Calm wind becoming north northeast around 5 mph.
Saturday
 
 Sunny, with a high near 79. North wind around 5 mph.
Saturday Night
 
 Partly cloudy, with a low around 56.
Sunday
 
 Partly sunny, with a high near 76.
Sunday Night
 
 A 40 percent chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 59.
Monday
 
 A 30 percent chance of showers before 1pm. Partly sunny, with a high near 77.
Monday Night
 
 Partly cloudy, with a low around 61.
Tuesday
 
 Mostly sunny, with a high near 82.
Tuesday Night
 
 Partly cloudy, with a low around 60.
Wednesday
 
 Mostly sunny, with a high near 80.

 

Forecast from NOAA-NWS for Storm Lake IA.