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Big Flat Lake, IL Weather Forecast
Big Flat Lake, IL Weather Forecast Date: 454 PM CST Tue Nov 03 2026
The area/counties/county of: Clinton County Il, including the cities of: Centralia and Salem.or toggle through each period.
Tonight... Rain with a slight chance of thunderstorms this evening, then a chance of rain after midnight. Lows in the mid 50s. South winds 10 to 15 mph with gusts up to 35 mph. Chance of rain near 100%.
Wednesday... Mostly cloudy. Cooler with highs in the mid 60s. Southwest winds 10 to 15 mph.
Wednesday Night... Mostly cloudy in the evening, then clearing. Cooler with lows in the lower 40s. Southwest winds around 5 mph.
Thursday... Sunny. Highs in the upper 60s. Southwest winds 5 to 10 mph.
Thursday Night... Partly cloudy in the evening, then becoming mostly cloudy. Lows in the mid 40s. Northwest winds around 5 mph.
Friday... Mostly cloudy in the morning, then becoming partly sunny. Highs in the upper 50s.
Friday Night... Partly cloudy. Lows in the mid 30s. Highs in the mid 50s.
Saturday... Partly cloudy. Lows in the mid 30s. Highs in the mid 50s.
Sunday... Mostly clear. Highs in the mid 60s. Lows in the mid 30s.
Monday... Mostly clear. Highs in the mid 60s. Lows in the mid 30s.
POP = Probability of Precipitation
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