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New Castle, IL Weather Forecast
New Castle, IL Weather Forecast Date: 1152 PM CDT Tue Oct 13 2026
The area/counties/county of: Williamson, including the city of Herrin.or toggle through each period.
Tonight... Mostly clear. Lows in the lower 70s. Southwest winds 5 to 10 mph.
Wednesday... Showers with a chance of thunderstorms. Highs in the lower 80s. Southwest winds around 5 mph. Chance of rain 90%.
Wednesday Night... A chance of thunderstorms in the evening. Mostly cloudy with a chance of showers. Lows in the upper 60s. Calm winds. Chance of rain 50%.
Thursday... Mostly cloudy in the morning, then becoming mostly sunny. A chance of showers. Highs in the upper 80s. Southeast winds 5 to 10 mph, becoming southwest 10 to 15 mph in the afternoon. Chance of rain 50%.
Thursday Night... Partly cloudy in the evening, then becoming mostly cloudy. A chance of showers. Cooler with lows in the lower 50s. Southwest winds 5 to 10 mph, increasing to northwest 15 to 20 mph after midnight. Chance of rain 50%.
Friday... Partly sunny in the morning, then clearing. Much cooler with highs in the lower 60s.
Friday Night... Mostly clear. Lows around 40. Highs in the lower 60s.
Saturday... Mostly clear. Lows around 40. Highs in the lower 60s.
Saturday Night... Clear. Lows in the upper 30s.
Sunday... Sunny. Highs in the upper 60s.
Sunday Night... Partly cloudy. Lows in the mid 40s. Highs in the lower 70s.
Monday... Partly cloudy. Lows in the mid 40s. Highs in the lower 70s.
Monday Night... Partly cloudy. Lows in the lower 50s. Highs in the upper 70s.
POP = Probability of Precipitation
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