Home

National Weather Service Forecast for: St. Charles County
Issued by: NWS National Weather Service Saint Louis, MO
Updated: 928 PM CDT Sat Aug 8 2026
St. Charles , MO
 
Tonight


Mostly Clear
Mostly Clear		 Sunday


Sunny
Sunny		 Sunday
Night

Mostly Clear
Mostly Clear		 Monday


Hot
Hot		 Monday
Night

Mostly Clear
Mostly Clear		 Tuesday


Hot
Hot		 Tuesday
Night

Thunder storm
Thunder storm		 Wednesday


Thunder storm
Thunder storm		 Wednesday
Night

Thunder storm
Thunder storm
Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F

 

Tonight
 
 Mostly clear. Lows in the lower 70s. South winds around 5 mph.
Sunday
 
 Sunny with highs in the mid 90s. South winds 10 to 15 mph. Heat index values up to 104.
Sunday Night
 
 Mostly clear. Humid with lows in the mid 70s. South winds 5 to 10 mph. Heat index values up to 103 early in the evening.
Monday
 
 Mostly sunny. Hot with highs in the mid 90s. Southwest winds 5 to 10 mph. Heat index values up to 111 in the afternoon.
Monday Night
 
 Mostly clear. Humid with lows in the upper 70s. South winds 5 to 10 mph. Heat index values up to 109 early in the evening.
Tuesday
 
 Mostly sunny. Hot with highs in the mid 90s. Heat index values up to 110.
Tuesday Night
 
 Partly cloudy. A slight chance of showers and thunderstorms after midnight. Lows in the upper 70s. Chance of rain 20 percent. Heat index values up to 105 early in the evening.
Wednesday
 
 Partly sunny. A slight chance of showers and thunderstorms in the morning, then a chance of showers and thunderstorms in the afternoon. Highs in the lower 90s. Chance of rain 40 percent. Heat index values up to 105.
Wednesday Night
 
 Partly cloudy in the evening, then becoming mostly cloudy. A chance of showers and thunderstorms. Lows in the lower 70s. Chance of rain 50 percent. Heat index values up to 105 early in the evening.
Thursday
 
 Showers and thunderstorms likely. Highs in the mid 80s.
Thursday Night
 
 Showers and thunderstorms likely. Lows around 70.
Friday
 
 Mostly cloudy with a chance of showers and thunderstorms. Highs in the mid 80s.
Friday Night
 
 Mostly cloudy with a chance of showers and thunderstorms. Lows in the upper 60s.
Saturday
 
 Mostly cloudy with a chance of showers and thunderstorms. Highs in the mid 80s.
Zone Forecast
 
 St. Charles County

 

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