Home

National Weather Service Forecast for: St. Charles County
Issued by: NWS National Weather Service Saint Louis, MO
Updated: 602 AM CDT Sun Sep 6 2026
St. Charles , MO
 
Today


Mostly Sunny
Mostly Sunny		 Tonight


Partly Cloudy
Partly Cloudy		 Labor
Day

Sunny
Sunny		 Monday
Night

Partly Cloudy
Partly Cloudy		 Tuesday


Hot
Hot		 Tuesday
Night

Mostly Clear
Mostly Clear		 Wednesday


Thunder storm
Thunder storm		 Wednesday
Night

Thunder storm
Thunder storm		 Thursday


Thunder storm
Thunder storm
Hi ≈90°F Lo ≈65°F Hi ≈85°F Lo ≈65°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈70°F Hi ≈85°F

 

Today
 
 Mostly sunny. Not as warm with highs around 90. Northeast winds 5 to 10 mph.
Tonight
 
 Mostly clear in the evening, then becoming partly cloudy. Lows in the mid 60s. Northeast winds 5 to 10 mph.
Labor Day
 
 Sunny. Highs in the upper 80s. East winds 5 to 10 mph.
Monday Night
 
 Partly cloudy in the evening, then becoming mostly clear. Lows in the lower 60s. East winds around 5 mph.
Tuesday
 
 Sunny, hot with highs in the mid 90s. South winds around 5 mph.
Tuesday Night
 
 Mostly clear. Not as cool with lows in the lower 70s.
Wednesday
 
 Mostly sunny. A slight chance of showers and thunderstorms in the afternoon. Hot with highs in the upper 90s. Chance of rain 20 percent. Heat index values up to 105 in the afternoon.
Wednesday Night
 
 Partly cloudy in the evening, then becoming mostly cloudy. A chance of thunderstorms. A chance of showers in the evening, then showers likely after midnight. Lows around 70. Chance of rain 70 percent. Heat index values up to 100 early in the evening.
Thursday
 
 Mostly cloudy in the morning, then becoming partly sunny. A slight chance of thunderstorms. A chance of showers, mainly in the morning. Not as warm with highs in the mid 80s. Chance of rain 50 percent.
Thursday Night
 
 Partly cloudy in the evening, then mostly clear with a slight chance of showers after midnight. Lows in the mid 60s. Chance of rain 20 percent.
Friday
 
 Sunny with a 20 percent chance of showers. Highs in the mid 80s.
Friday Night
 
 Mostly clear with a slight chance of showers and thunderstorms. Lows in the mid 60s. Chance of rain 20 percent.
Saturday
 
 Sunny. A slight chance of showers in the morning. Highs around 90. Chance of rain 20 percent.
Zone Forecast
 
 St. Charles County

 

Forecast from NOAA-NWS for St. Charles County. (Zone forecast)