National Weather Service Forecast for: Crystal Lake IL
Issued by: National Weather Service Chicago, IL
Updated: 9:46 am CDT May 4, 2026
 
This
Afternoon
This Afternoon: Sunny, with a high near 77. Breezy, with a west southwest wind around 20 mph, with gusts as high as 30 mph.
Sunny and
Breezy

 Tonight

Tonight: Scattered showers and thunderstorms before 11pm, then isolated showers between 11pm and 1am. Mostly cloudy, with a low around 47. West southwest wind 10 to 15 mph becoming north northwest after midnight. Winds could gust as high as 20 mph. Chance of precipitation is 50%.
Scattered
T-storms then
Isolated
Showers
 Tuesday

Tuesday: A 20 percent chance of showers after 1pm. Mostly cloudy, with a high near 55. North northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Mostly Cloudy
then Slight
Chance
Showers
 Tuesday
Night
Tuesday Night: Mostly cloudy, with a low around 38. North northwest wind around 5 mph, with gusts as high as 10 mph.
Mostly Cloudy

 Wednesday

Wednesday: Partly sunny, with a high near 56. Northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Partly Sunny

 Wednesday
Night
Wednesday Night: Mostly cloudy, with a low around 38.
Mostly Cloudy

 Thursday

Thursday: Partly sunny, with a high near 58.
Partly Sunny

 Thursday
Night
Thursday Night: Mostly cloudy, with a low around 41.
Mostly Cloudy

 Friday

Friday: Mostly sunny, with a high near 62.
Mostly Sunny
Hi 77 °F Lo 47 °F Hi 55 °F Lo 38 °F Hi 56 °F Lo 38 °F Hi 58 °F Lo 41 °F Hi 62 °F

Hazardous Weather Outlook
 

This Afternoon
 
 Sunny, with a high near 77. Breezy, with a west southwest wind around 20 mph, with gusts as high as 30 mph.
Tonight
 
 Scattered showers and thunderstorms before 11pm, then isolated showers between 11pm and 1am. Mostly cloudy, with a low around 47. West southwest wind 10 to 15 mph becoming north northwest after midnight. Winds could gust as high as 20 mph. Chance of precipitation is 50%.
Tuesday
 
 A 20 percent chance of showers after 1pm. Mostly cloudy, with a high near 55. North northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Tuesday Night
 
 Mostly cloudy, with a low around 38. North northwest wind around 5 mph, with gusts as high as 10 mph.
Wednesday
 
 Partly sunny, with a high near 56. Northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Wednesday Night
 
 Mostly cloudy, with a low around 38.
Thursday
 
 Partly sunny, with a high near 58.
Thursday Night
 
 Mostly cloudy, with a low around 41.
Friday
 
 Mostly sunny, with a high near 62.
Friday Night
 
 Partly cloudy, with a low around 40.
Saturday
 
 Sunny, with a high near 66.
Saturday Night
 
 Partly cloudy, with a low around 45.
Sunday
 
 Partly sunny, with a high near 66.

 

Forecast from NOAA-NWS for Crystal Lake IL.