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National Weather Service Forecast for: St. Charles County
Issued by: NWS National Weather Service Saint Louis, MO
Updated: 453 AM CDT Sun Jul 26 2026
St. Charles , MO
 
Today


Thunder storm
Thunder storm
Tonight


Partly Cloudy
Partly Cloudy
Monday


Hot
Hot
Monday
Night

Mostly Clear
Mostly Clear
Tuesday


Mostly Sunny
Mostly Sunny
Tuesday
Night

Partly Cloudy
Partly Cloudy
Wednesday


Mostly Clear
Mostly Clear
Wednesday
Night

Mostly Clear
Mostly Clear
Thursday


Mostly Clear
Mostly Clear
Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈95°F Lo ≈75°F Hi ≈85°F Lo ≈65°F Hi ≈85°F

 

Today
 
Mostly cloudy this morning, then becoming mostly sunny. Patchy fog this morning. A slight chance of showers and thunderstorms. Hot with highs in the mid 90s. Southwest winds around 5 mph. Chance of rain 20 percent. Heat index values up to 117.
Tonight
 
Partly cloudy. Humid with lows in the upper 70s. South winds around 5 mph. Heat index values up to 116 early in the evening.
Monday
 
Sunny, hot with highs in the upper 90s. Southwest winds 5 to 10 mph. Heat index values up to 114.
Monday Night
 
Mostly clear. Humid with lows in the upper 70s. Southwest winds 5 to 10 mph. Heat index values up to 112 early in the evening.
Tuesday
 
Mostly sunny. Humid with highs in the lower 90s. Northwest winds 5 to 10 mph. Heat index values up to 105.
Tuesday Night
 
Partly cloudy. Lows in the lower 70s. Heat index values up to 100 early in the evening.
Wednesday
 
Mostly clear. Highs in the upper 80s.
Wednesday Night
 
Mostly clear. Lows in the upper 60s.
Thursday
 
Mostly clear. Highs in the upper 80s.
Thursday Night
 
Partly cloudy in the evening, then mostly cloudy with a slight chance of showers after midnight. Lows in the upper 60s. Chance of rain 20 percent.
Friday
 
Partly sunny with a slight chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the mid 80s. Chance of rain 20 percent.
Friday Night
 
A slight chance of thunderstorms in the evening. Partly cloudy with a chance of showers. Lows in the upper 60s. Chance of rain 40 percent.
Saturday
 
Mostly sunny with a slight chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the mid 80s. Chance of rain 20 percent.
Zone Forecast
 
St. Charles County

 

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