| National Weather Service Forecast for:
St. Charles County Issued by: NWS National Weather Service Saint Louis, MO |
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| Updated: 1128 AM CDT Wed Aug 19 2026 | ||||||||||||||||||
| St. Charles , MO | ||||||||||||||||||
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| This Afternoon |
Mostly cloudy with a chance of showers. A slight chance of thunderstorms early, then a chance of thunderstorms. Highs in the lower 80s. South winds around 5 mph. Chance of rain 50 percent. |
| Tonight |
Mostly cloudy. A chance of showers and thunderstorms, mainly in the evening. Patchy fog after midnight. Lows in the upper 60s. Northeast winds around 5 mph. Chance of rain 50 percent. |
| Thursday |
Mostly cloudy in the morning, then becoming mostly sunny. Patchy fog in the morning. Highs in the mid 80s. Northeast winds around 5 mph. |
| Thursday Night |
Partly cloudy in the evening, then becoming mostly clear. Lows in the mid 60s. Northeast winds around 5 mph in the evening, becoming light and variable. |
| Friday |
Sunny. Highs in the upper 80s. Light and variable winds, becoming west around 5 mph in the afternoon. |
| Friday Night |
Mostly clear in the evening, then partly cloudy with a slight chance of showers and thunderstorms after midnight. Lows in the upper 60s. Chance of rain 20 percent. |
| Saturday |
Sunny. A slight chance of showers in the morning. Highs in the mid 80s. Chance of rain 20 percent. |
| Saturday Night |
Mostly clear. Lows in the mid 60s. |
| Sunday |
Mostly sunny. Highs in the lower 80s. |
| Sunday Night |
Partly cloudy. A slight chance of showers and thunderstorms after midnight. Lows in the mid 60s. Chance of rain 20 percent. |
| Monday |
Partly sunny. Highs in the mid 80s. |
| Monday Night |
Partly cloudy. Lows in the upper 60s. |
| Tuesday |
Partly cloudy. Highs in the upper 80s. |
| Zone Forecast |
St. Charles County |
Forecast from NOAA-NWS for St. Charles County. (Zone forecast)