| National Weather Service Forecast for:
St. Charles County Issued by: NWS National Weather Service Saint Louis, MO |
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| Updated: 914 PM CDT Sat Jun 27 2026 | ||||||||||||||||||
| St. Charles , MO | ||||||||||||||||||
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| Tonight |
Partly cloudy. A slight chance of showers and thunderstorms this evening, then a chance of showers and thunderstorms after midnight. Patchy fog after midnight. Lows in the lower 70s. South winds around 5 mph. Chance of rain 30 percent. |
| Sunday |
Patchy fog in the morning. Sunny with highs in the lower 90s. South winds 5 to 10 mph. Heat index values up to 106 in the afternoon. |
| Sunday Night |
Clear in the evening, then becoming partly cloudy. Humid with lows in the mid 70s. South winds 5 to 10 mph. Heat index values up to 107 early in the evening. |
| Monday |
Mostly sunny. Hot with highs in the mid 90s. South winds 5 to 10 mph. Heat index values up to 111. |
| Monday Night |
Mostly clear. Humid with lows in the mid 70s. South winds 5 to 10 mph. Heat index values up to 110 early in the evening. |
| Tuesday |
Clear, hot. Highs in the mid 90s. |
| Tuesday Night |
Clear, hot. Lows in the mid 70s. |
| Wednesday |
Clear, hot. Highs in the mid 90s. |
| Wednesday Night |
Mostly clear. Lows in the mid 70s. Heat index values up to 110 early in the evening. |
| Thursday |
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 105. |
| Thursday Night |
Partly cloudy in the evening, then becoming mostly clear. Lows in the mid 70s. Heat index values up to 105 early in the evening. |
| Zone Forecast |
St. Charles County |
Forecast from NOAA-NWS for St. Charles County. (Zone forecast)