| National Weather Service Forecast for:
St. Charles County Issued by: NWS National Weather Service Saint Louis, MO |
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| Updated: 1222 PM CDT Wed Sep 2 2026 | ||||||||||||||||||
| St. Charles , MO | ||||||||||||||||||
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| This Afternoon |
Sunny, hot. Near steady temperature in the upper 90s. Southwest winds 5 to 10 mph with gusts up to 20 mph. |
| Tonight |
Mostly clear. Lows in the upper 70s. South winds around 5 mph. Heat index values up to 104 early in the evening. |
| Thursday |
Sunny, hot with highs in the upper 90s. Southwest winds 5 to 10 mph. Heat index values up to 105. |
| Thursday Night |
Mostly clear. Lows in the upper 70s. South winds around 5 mph. Heat index values up to 104 early in the evening. |
| Friday |
Sunny, hot with highs in the upper 90s. Southwest winds around 5 mph. |
| Friday Night |
Mostly clear in the evening, then becoming partly cloudy. Lows in the upper 70s. Heat index values up to 105 early in the evening. |
| Saturday |
Mostly sunny with a slight chance of showers and thunderstorms. Hot with highs in the upper 90s. Chance of rain 20 percent. Heat index values up to 105. |
| Saturday Night |
Partly cloudy in the evening, then clearing. A 20 percent chance of showers. Lows in the mid 70s. Heat index values up to 105 early in the evening. |
| Sunday |
Mostly sunny. A slight chance of showers and thunderstorms in the afternoon. Highs in the mid 90s. Chance of rain 20 percent. Heat index values up to 100. |
| Monday Night |
A slight chance of thunderstorms in the evening. Partly cloudy with a slight chance of showers. Lows around 70. Chance of rain 20 percent. |
| Tuesday |
Mostly sunny. Highs in the lower 90s. |
| Zone Forecast |
St. Charles County |
Forecast from NOAA-NWS for St. Charles County. (Zone forecast)