National Weather Service Forecast for: De Kalb IL
Issued by: National Weather Service Chicago, IL
Updated: 3:01 am CDT Jun 22, 2026
 
Today

Today: A 20 percent chance of showers after 4pm.  Mostly sunny, with a high near 74. North northeast wind around 10 mph, with gusts as high as 20 mph.
Partly Sunny
then Slight
Chance
Showers
Tonight

Tonight: A 20 percent chance of showers before 10pm.  Mostly clear, with a low around 51. North northeast wind 5 to 10 mph.
Slight Chance
Showers then
Mostly Clear
Tuesday

Tuesday: Increasing clouds, with a high near 76. North northeast wind around 5 mph becoming calm.
Increasing
Clouds

Tuesday
Night
Tuesday Night: Mostly cloudy, with a low around 57. South wind around 5 mph, with gusts as high as 10 mph.
Mostly Cloudy

Wednesday

Wednesday: A chance of showers, then showers likely and possibly a thunderstorm after 1pm.  Partly sunny, with a high near 78. West southwest wind 5 to 10 mph, with gusts as high as 20 mph.  Chance of precipitation is 60%.
Chance
Showers then
Showers
Likely
Wednesday
Night
Wednesday Night: A 30 percent chance of showers and thunderstorms before 1am.  Partly cloudy, with a low around 58.
Chance
T-storms then
Chance
Showers
Thursday

Thursday: A 20 percent chance of showers and thunderstorms after 1pm.  Mostly sunny, with a high near 77.
Mostly Sunny
then Slight
Chance
T-storms
Thursday
Night
Thursday Night: Partly cloudy, with a low around 56.
Partly Cloudy

Friday

Friday: Mostly sunny, with a high near 78.
Mostly Sunny

Hi 74 °F Lo 51 °F Hi 76 °F Lo 57 °F Hi 78 °F Lo 58 °F Hi 77 °F Lo 56 °F Hi 78 °F

Hazardous Weather Outlook
 

Today
 
A 20 percent chance of showers after 4pm. Mostly sunny, with a high near 74. North northeast wind around 10 mph, with gusts as high as 20 mph.
Tonight
 
A 20 percent chance of showers before 10pm. Mostly clear, with a low around 51. North northeast wind 5 to 10 mph.
Tuesday
 
Increasing clouds, with a high near 76. North northeast wind around 5 mph becoming calm.
Tuesday Night
 
Mostly cloudy, with a low around 57. South wind around 5 mph, with gusts as high as 10 mph.
Wednesday
 
A chance of showers, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 78. West southwest wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.
Wednesday Night
 
A 30 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 58.
Thursday
 
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 77.
Thursday Night
 
Partly cloudy, with a low around 56.
Friday
 
Mostly sunny, with a high near 78.
Friday Night
 
Mostly cloudy, with a low around 58.
Saturday
 
Partly sunny, with a high near 80.
Saturday Night
 
A chance of showers. Mostly cloudy, with a low around 64.
Sunday
 
Mostly sunny, with a high near 86.

 

Forecast from NOAA-NWS for De Kalb IL.