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City of Decatur, IllinoisDecatur, IL 7-Day Night Weather Forecast
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Decatur, IL Weather Forecast
Decatur, IL Weather Forecast Date: 1238 AM CDT Sat Aug 15 2026
The area/counties/county of: Macon, including the city of Decatur.or toggle through each period.
Rest of Tonight... Mostly cloudy with a chance of showers and thunderstorms. Near steady temperature in the mid 70s. Southeast winds 5 to 10 mph with gusts up to 20 mph. Chance of rain 50%.
Saturday... Mostly cloudy with a chance of showers and thunderstorms in the morning, then partly sunny with a slight chance of showers in the afternoon. Humid with highs in the lower 90s. Southeast winds 5 to 10 mph, becoming southwest in the afternoon. Chance of rain 50%. Heat index values up to 108 in the afternoon.
Saturday Night... Partly cloudy. A slight chance of showers after midnight. Humid with lows in the mid 70s. Southwest winds 5 to 10 mph. Chance of rain 20%.
Sunday... Partly sunny. Humid with highs in the upper 80s. Northwest winds 5 to 10 mph. Heat index values up to 101.
Sunday Night... Partly cloudy. Humid with lows in the upper 60s. Northwest winds 5 to 10 mph.
Monday... Partly cloudy. Highs in the mid 80s. Lows in the lower 60s.
Monday Night... Partly cloudy. Highs in the mid 80s. Lows in the lower 60s.
Tuesday... Sunny. Highs in the mid 80s.
Tuesday Night... Mostly clear in the evening, then becoming partly cloudy. Lows in the upper 60s.
Wednesday... Partly sunny. Highs in the upper 80s.
Wednesday Night... Mostly cloudy. A chance of showers in the evening. Lows in the mid 60s. Chance of rain 30%.
Thursday... Partly sunny. Highs around 80.
Thursday Night... Partly cloudy. Lows in the lower 60s. Highs around 80.
POP = Probability of Precipitation
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