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Alton Lake, IL Weather Forecast
Alton Lake, IL Weather Forecast Date: 1132 AM CDT Tue Aug 25 2026
The area/counties/county of: Madison County Il, including the cities of: Alton, Edwardsville, Belleville, Cahokia, Saint Charles, and Saint Louis.or toggle through each period.
This Afternoon... Mostly sunny. Highs in the mid 80s. Southeast winds around 5 mph.
Tonight... Mostly cloudy. Lows in the upper 60s. Southeast winds around 5 mph.
Wednesday... Mostly sunny. A slight chance of showers and thunderstorms in the afternoon. Highs in the upper 80s. Southwest winds 5 to 10 mph. Chance of rain 20%.
Wednesday Night... Mostly cloudy with a chance of showers and thunderstorms in the evening, then mostly clear after midnight. Lows in the mid 60s. Northwest winds around 5 mph. Chance of rain 40%.
Thursday... Sunny. Highs in the mid 80s. North winds 5 to 10 mph.
Thursday Night... Mostly clear. Lows in the mid 60s.
Friday... Sunny. Highs in the mid 80s.
Friday Night... Mostly clear. Lows in the mid 60s.
Saturday... Partly cloudy. Highs in the upper 80s. Lows in the upper 60s.
Saturday Night... Partly cloudy. Highs in the upper 80s. Lows in the upper 60s.
Sunday... Mostly sunny. Highs in the mid 90s.
Sunday Night... Mostly clear. Lows in the mid 70s.
POP = Probability of Precipitation
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