National Weather Service Forecast for: Mount Prospect IL
Issued by: National Weather Service Chicago, IL
Updated: 2:20 am CDT Aug 26, 2026
 
Overnight

Overnight: A 20 percent chance of showers. Mostly cloudy, with a low around 66. South southwest wind around 10 mph, with gusts as high as 15 mph.
Slight Chance
Showers

 Wednesday

Wednesday: A chance of showers and thunderstorms before 2pm, then a slight chance of showers between 2pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Partly sunny, with a high near 84. South southwest wind 10 to 15 mph becoming west in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 30%.
Chance
Showers then
Slight Chance
T-storms
 Wednesday
Night
Wednesday Night: Mostly clear, with a low around 65. Northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Mostly Clear

 Thursday

Thursday: A slight chance of showers between 1pm and 4pm. Increasing clouds, with a high near 80. Northwest wind 5 to 10 mph. Chance of precipitation is 20%.
Sunny then
Slight Chance
Showers
 Thursday
Night
Thursday Night: Mostly clear, with a low around 62. Northeast wind around 5 mph becoming calm in the evening.
Mostly Clear

 Friday

Friday: Sunny, with a high near 80.
Sunny

 Friday
Night
Friday Night: Partly cloudy, with a low around 63.
Partly Cloudy

 Saturday

Saturday: Partly sunny, with a high near 82.
Partly Sunny

 Saturday
Night
Saturday Night: Mostly cloudy, with a low around 68.
Mostly Cloudy
Lo 66 °F Hi 84 °F Lo 65 °F Hi 80 °F Lo 62 °F Hi 80 °F Lo 63 °F Hi 82 °F Lo 68 °F

Hazardous Weather Outlook
 

Overnight
 
 A 20 percent chance of showers. Mostly cloudy, with a low around 66. South southwest wind around 10 mph, with gusts as high as 15 mph.
Wednesday
 
 A chance of showers and thunderstorms before 2pm, then a slight chance of showers between 2pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Partly sunny, with a high near 84. South southwest wind 10 to 15 mph becoming west in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 30%.
Wednesday Night
 
 Mostly clear, with a low around 65. Northwest wind 5 to 10 mph, with gusts as high as 15 mph.
Thursday
 
 A slight chance of showers between 1pm and 4pm. Increasing clouds, with a high near 80. Northwest wind 5 to 10 mph. Chance of precipitation is 20%.
Thursday Night
 
 Mostly clear, with a low around 62. Northeast wind around 5 mph becoming calm in the evening.
Friday
 
 Sunny, with a high near 80.
Friday Night
 
 Partly cloudy, with a low around 63.
Saturday
 
 Partly sunny, with a high near 82.
Saturday Night
 
 Mostly cloudy, with a low around 68.
Sunday
 
 Partly sunny, with a high near 87.
Sunday Night
 
 Partly cloudy, with a low around 72.
Monday
 
 Partly sunny, with a high near 87.
Monday Night
 
 A chance of showers. Mostly cloudy, with a low around 71.
Tuesday
 
 A chance of showers. Mostly sunny, with a high near 85.

 

Forecast from NOAA-NWS for Mount Prospect IL.