National Weather Service Forecast for: Crystal Lake IL
Issued by: National Weather Service Chicago, IL
Updated: 8:56 pm CDT Aug 8, 2025
 
Tonight

Tonight: Partly cloudy, with a low around 73. South wind around 10 mph.
Partly Cloudy

 Saturday

Saturday: A 20 percent chance of showers and thunderstorms after 4pm. Sunny, with a high near 92. Heat index values as high as 101. South wind 10 to 15 mph, with gusts as high as 30 mph.
Sunny then
Slight Chance
T-storms
 Saturday
Night
Saturday Night: A 40 percent chance of showers and thunderstorms, mainly after 7pm. Mostly cloudy, with a low around 71. South southwest wind around 10 mph, with gusts as high as 20 mph.
Chance
T-storms

 Sunday

Sunday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87. Heat index values as high as 95. South southwest wind around 10 mph, with gusts as high as 20 mph.
Chance
T-storms

 Sunday
Night
Sunday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 70. South wind around 5 mph, with gusts as high as 10 mph.
Chance
T-storms

 Monday

Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 84. Chance of precipitation is 60%.
Chance
T-storms then
Showers
Likely
 Monday
Night
Monday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 68.
Chance
T-storms

 Tuesday

Tuesday: A chance of showers and thunderstorms. Partly sunny, with a high near 84.
Chance
T-storms

 Tuesday
Night
Tuesday Night: Partly cloudy, with a low around 65.
Partly Cloudy
Lo 73 °F Hi 92 °F Lo 71 °F Hi 87 °F Lo 70 °F Hi 84 °F Lo 68 °F Hi 84 °F Lo 65 °F

 

Tonight
 
 Partly cloudy, with a low around 73. South wind around 10 mph.
Saturday
 
 A 20 percent chance of showers and thunderstorms after 4pm. Sunny, with a high near 92. Heat index values as high as 101. South wind 10 to 15 mph, with gusts as high as 30 mph.
Saturday Night
 
 A 40 percent chance of showers and thunderstorms, mainly after 7pm. Mostly cloudy, with a low around 71. South southwest wind around 10 mph, with gusts as high as 20 mph.
Sunday
 
 A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87. Heat index values as high as 95. South southwest wind around 10 mph, with gusts as high as 20 mph.
Sunday Night
 
 A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 70. South wind around 5 mph, with gusts as high as 10 mph.
Monday
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 84. Chance of precipitation is 60%.
Monday Night
 
 A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 68.
Tuesday
 
 A chance of showers and thunderstorms. Partly sunny, with a high near 84.
Tuesday Night
 
 Partly cloudy, with a low around 65.
Wednesday
 
 Mostly sunny, with a high near 84.
Wednesday Night
 
 Partly cloudy, with a low around 65.
Thursday
 
 Mostly sunny, with a high near 85.
Thursday Night
 
 Partly cloudy, with a low around 67.
Friday
 
 Mostly sunny, with a high near 88.

 

Forecast from NOAA-NWS for Crystal Lake IL.