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Arrowhead Lake, IL Weather Forecast
Arrowhead Lake, IL Weather Forecast Date: 1017 PM CDT Wed Sep 23 2026
The area/counties/county of: Piatt, including the city of Monticello.or toggle through each period.
Rest of Tonight... Cloudy with patchy very light drizzle. Lows in the upper 50s. Northeast winds 5 to 10 mph.
Thursday... Mostly cloudy in the morning, then becoming partly sunny. Highs in the lower 70s. Northeast winds 5 to 10 mph.
Thursday Night... Mostly cloudy in the evening, then becoming partly cloudy. Lows in the upper 50s. East winds 5 to 10 mph.
Friday... Partly sunny. Highs in the lower 70s. East winds 5 to 10 mph.
Friday Night... Partly cloudy in the evening, then becoming mostly cloudy. Lows in the lower 50s. East winds around 5 mph.
Saturday... Mostly cloudy. Highs in the lower 70s. Lows in the mid 50s.
Sunday... Mostly cloudy. Highs in the lower 70s. Lows in the mid 50s.
Sunday Night... Partly cloudy. Lows in the lower 50s.
Monday... Sunny. Highs in the upper 70s.
Monday Night... Mostly clear in the evening, then becoming partly cloudy. Lows in the mid 50s.
Tuesday... Mostly sunny. A chance of showers in the afternoon. Highs in the lower 80s. Chance of rain 30%.
Tuesday Night... Showers likely. Lows in the lower 60s. Chance of rain 60%.
POP = Probability of Precipitation
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