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Southern Illnois University, IL Weather Forecast
Southern Illnois University, IL Weather Forecast Date: 913 PM CDT Sun Aug 23 2026
The area/counties/county of: Williamson, including the city of Herrin.or toggle through each period.
Tonight... Partly cloudy. Patchy fog after midnight. Lows in the upper 50s. Northwest winds around 5 mph this evening, becoming light and variable.
Monday... Patchy fog in the morning. Mostly sunny. Highs in the mid 80s. Calm winds, becoming northwest around 5 mph in the afternoon.
Monday Night... Mostly clear. Lows in the lower 60s. East winds around 5 mph in the evening, becoming light and variable.
Tuesday... Sunny. Highs in the upper 80s. East winds around 5 mph.
Tuesday Night... Mostly clear in the evening, then becoming partly cloudy. Lows in the mid 60s. East winds around 5 mph in the evening, becoming light and variable.
Wednesday... Partly cloudy. Highs around 90. Lows in the upper 60s.
Wednesday Night... Partly cloudy. Highs around 90. Lows in the upper 60s.
Thursday... Mostly clear. Highs around 90. Lows in the mid 60s.
Friday... Mostly clear. Highs around 90. Lows in the mid 60s.
Saturday... Partly cloudy. Highs around 90. Lows in the upper 60s.
POP = Probability of Precipitation
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