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