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Jefferson County, IL 7-Day Night Weather Forecast
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Jefferson County, IL Weather Forecast
Jefferson County, IL Weather Forecast Date: 734 PM CST Mon Mar 02 2026
The area/counties/county of: Jefferson, including the city of Mount Vernon.or toggle through each period.
Tonight... Cloudy. Patchy fog. Rain showers with a slight chance of thunderstorms after midnight. Near steady temperature in the upper 30s. East winds around 5 mph. Chance of rain 80%.
Tuesday... Cloudy. Patchy fog in the morning. Showers, mainly in the morning. Not as cool with highs in the lower 60s. Southeast winds 5 to 10 mph, becoming south in the afternoon. Chance of rain 90%.
Tuesday Night... Showers likely. A chance of thunderstorms after midnight. Not as cool. Near steady temperature in the mid 50s. Southeast winds around 5 mph. Chance of rain 70%.
Wednesday... A chance of thunderstorms. Showers. Highs in the upper 60s. South winds 5 to 10 mph. Chance of rain 80%.
Wednesday Night... A chance of thunderstorms. Showers. Lows in the upper 50s. South winds 5 to 10 mph. Chance of rain 80%.
Thursday... A chance of thunderstorms. Showers. Highs in the lower 70s. Chance of rain 80%.
Thursday Night... Mostly cloudy with a chance of showers. Lows in the mid 50s. Chance of rain 50%.
Friday... Mostly sunny. A chance of showers and thunderstorms in the morning. Highs in the upper 70s. Chance of rain 40%.
Friday Night... Partly cloudy in the evening, then mostly cloudy with a chance of showers after midnight. Lows in the lower 60s. Chance of rain 50%.
Saturday... Showers with a chance of thunderstorms in the morning, then showers likely in the afternoon. Highs around 70. Chance of rain 80%.
Saturday Night... Mostly cloudy with a 40% chance of showers. Lows around 50.
Sunday... Mostly cloudy with a 30% chance of showers. Highs in the mid 60s. Lows in the lower 50s.
Sunday Night... Mostly cloudy with a 30% chance of showers. Highs in the mid 60s. Lows in the lower 50s.
POP = Probability of Precipitation
Jefferson County Radar Loop
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