| NWS Forecast for: St. Charles County Issued by: National Weather Service Saint Louis, MO Last Update: 1053 PM CDT Tue Jul 21 2026 | |
| Overnight: Mostly clear. Cooler with lows in the upper 60s. North winds 5 to 10 mph. Wednesday: Mostly sunny. Highs in the lower 80s. North winds 5 to 10 mph. Wednesday Night: Mostly cloudy in the evening, then clearing. Lows in the lower 60s. Northeast winds 5 to 10 mph. Thursday: Mostly sunny. Highs in the lower 80s. East winds around 5 mph. Thursday Night: Partly cloudy in the evening, then mostly cloudy with a slight chance of showers after midnight. Lows in the lower 60s. East winds around 5 mph. Chance of rain 20 percent. Friday: Partly sunny in the morning, then becoming mostly cloudy. A chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the upper 70s. Chance of rain 50 percent. Friday Night: Mostly cloudy. A slight chance of showers and thunderstorms in the evening, then a chance of showers and thunderstorms after midnight. Lows in the mid 60s. Chance of rain 50 percent. Saturday: Mostly sunny. A slight chance of showers and thunderstorms in the morning. Warmer with highs in the upper 80s. Chance of rain 20 percent. Heat index values up to 100 in the afternoon. Saturday Night Through Monday Night: Mostly clear. Hot. Lows in the mid 70s. Highs in the mid 90s. Heat index values up to 110. Tuesday: Mostly sunny. Highs in the lower 90s. Heat index values up to 100. | |
| Zone Forecast: St. Charles County | |
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