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City of O'Fallon, MOO'Fallon, MO 7-Day Night Weather Forecast
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O'Fallon, MO Weather Forecast
O'Fallon, MO Weather Forecast Date: 1028 PM CDT Sun Sep 06 2026
The area/counties/county of: Madison County Il, including the cities of: Alton, Edwardsville, Belleville, Cahokia, Saint Charles, and Saint Louis.or toggle through each period.
Overnight... Mostly cloudy. Lows in the mid 60s. Northeast winds around 5 mph with gusts up to 20 mph.
Labor Day... Sunny. Highs in the upper 80s. East winds 5 to 10 mph.
Monday Night... Mostly clear. Lows in the mid 60s. East winds 5 to 10 mph.
Tuesday... Mostly sunny. Hot with highs in the mid 90s. Southeast winds around 5 mph.
Tuesday Night... Mostly clear. Lows in the lower 70s. South winds 5 to 10 mph.
Wednesday... Mostly sunny. A slight chance of showers and thunderstorms in the afternoon. Hot with highs in the upper 90s. Chance of rain 20%. Heat index values up to 105 in the afternoon.
Wednesday Night... A chance of thunderstorms. Showers. Lows in the upper 60s. Chance of rain 80%. Heat index values up to 100 early in the evening.
Thursday... Mostly cloudy in the morning, then becoming partly sunny. A slight chance of thunderstorms. A chance of showers, mainly in the morning. Not as warm with highs in the mid 80s. Chance of rain 50%.
Thursday Night... Partly cloudy with a slight chance of showers in the evening, then mostly clear after midnight. Lows in the lower 60s. Chance of rain 20%.
Friday... Sunny. Highs in the mid 80s.
Friday Night... Mostly clear with a slight chance of thunderstorms. A slight chance of showers in the evening, then a chance of showers after midnight. Lows in the mid 60s. Chance of rain 30%.
Saturday... Mostly sunny. A chance of showers with a slight chance of thunderstorms in the morning. Highs around 90. Chance of rain 30%.
Saturday Night... Mostly clear in the evening, then becoming partly cloudy. A slight chance of thunderstorms. A slight chance of showers in the evening, then a chance of showers after midnight. Lows in the upper 60s. Chance of rain 30%.
POP = Probability of Precipitation
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