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National Weather Service Forecast for: St. Charles County
Issued by: NWS National Weather Service Saint Louis, MO
Updated: 838 AM CDT Fri Jul 18 2025
St. Charles , MO
 
Rest
Of Today

Thunder storm
Thunder storm
Tonight


Thunder storm
Thunder storm
Saturday


Thunder storm
Thunder storm
Saturday
Night

Thunder storm
Thunder storm
Sunday


Thunder storm
Thunder storm
Sunday
Night

Thunder storm
Thunder storm
Monday


Thunder storm
Thunder storm
Monday
Night

Thunder storm
Thunder storm
Tuesday


Thunder storm
Thunder storm
Hi ≈85°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F

 

Rest Of Today
 
Cloudy early this morning, then partly sunny with a chance of showers and thunderstorms this afternoon. Highs in the upper 80s. East winds around 5 mph. Chance of rain 30 percent.
Tonight
 
Mostly cloudy in the evening, then becoming partly cloudy. A chance of showers and thunderstorms. Humid with lows in the lower 70s. South winds around 5 mph. Chance of rain 40 percent.
Saturday
 
Mostly sunny with a chance of showers and thunderstorms. Humid with highs in the lower 90s. Southwest winds 5 to 10 mph. Chance of rain 50 percent. Heat index values up to 107 in the afternoon.
Saturday Night
 
Partly cloudy with a slight chance of showers and thunderstorms. Humid with lows in the mid 70s. Southwest winds around 5 mph. Chance of rain 20 percent. Heat index values up to 104 early in the evening.
Sunday
 
Mostly sunny. A slight chance of showers and thunderstorms in the morning, then a chance of showers and thunderstorms in the afternoon. Humid with highs in the mid 90s. Southwest winds around 5 mph. Chance of rain 30 percent. Heat index values up to 108.
Sunday Night
 
Partly cloudy with a chance of showers and thunderstorms. Lows in the mid 70s. Chance of rain 40 percent. Heat index values up to 105 early in the evening.
Monday
 
Mostly sunny with a slight chance of showers and thunderstorms. Highs in the mid 90s. Chance of rain 20 percent. Heat index values up to 110.
Monday Night
 
Mostly clear. A slight chance of showers and thunderstorms. Hot. Lows in the upper 70s.
Tuesday
 
Mostly clear. A slight chance of showers and thunderstorms. Hot. Highs in the mid 90s.
Tuesday Night
 
Mostly clear. Hot. Lows in the upper 70s.
Wednesday
 
Mostly clear. Hot. Highs in the upper 90s.
Wednesday Night
 
Mostly clear. Hot. Lows in the upper 70s.
Thursday
 
Mostly clear. Hot. Highs in the upper 90s.
Zone Forecast
 
St. Charles County

 

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